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That’s a great comment. In reality, the manufactures are producing these things faster than the regulatory bodies can keep up. Merely disclosing a floating neutral is enough to keep them off the hook for now at least. This was first mandated for the generator industry, and It’s ultimately the installers responsibility for how they are connected and used. These power packs have a least off-set the risks with built-in GFCI’s for personal shock protection, but that does not satisfy the long standing rules for bonding that the trailer industry must follow. This is directly related to the trailer “hot-skin” issue that was bandied around for years. They recently codified long overdue requirements for trailer Ground Monitor Interrupters (GMI) that will be phased in over the next few years. Similar to the EMS (except it can’t be by-passed), the GMI’s will prevent the use of non-bonded power supplies, and it will be non-optional for new trailers. We watch with interest how this story fully evolves! Cheers! Geoff

Thanks for trying to help everyone. I wish Oliver would let us owners have and electrical diagram so we can tell where all the relays and circut breakers are hidden. After countless hours of testing and looking around I finally found a breaker hidden at the bottom of the trailer below the negitive ground terminal on the outside of the battery box. There are two switches on the breaker. One is on the front side and easy to see but, the other is underneath the breaker and is a swing arm thats hard to see. That was the one that popped. Everythings is honky dory now. Thanks again for trying to help....I really appreciated it.

The bonding plug needs to be at the source -- the Bluetti or generator outlets. Not an outlet in the trailer. Because the Bluetti outlet has nothing connected to the ground, the bonding plug cannot join the ground and neutral. Therefor a one-to-three outlet adapter can be plugged into the Bluetti, one of the three adapter outlets gets the bonding plug, another gets the trailer feed cord, and the third is a spare. That effectively bonds the ground and neutral. Bonding at the power source has always been required by code, these power packs just add a new dynamic. Someone had an idea to use the EMS bypass "in a pinch." This isn't risk free, but it would be fine for getting the lights on while finding the bonding plug. The EMS is actually protecting the trailer from an un-bonded neutral that the bonding plug fixes. Keep in mind that these power supplies are perfectly fine for single power cord loads as designed. They are not designed to be connected to a trailer where the wiring system assumes a bonded supply. Cheers! Geoff

Into the outlet on the generator. I believe this is an artifact of the lack of a grounding rod and grounded electrical system on the trailer (which would be totally impractical).

Not really. Lots of people have RVs with no EMS system at all. The EMS cuts off power to your rig if the voltage is too high/low, the wires are not connected properly, or the source has the wrong Hertz (cycles per second). Cheap generators can have all of those problems. Shore power can be wired incorrectly or have voltage issues. Check your specs, but most new Bluetti power stations use a pure sine-wave inverter. That means the power should be "clean" enough for sensitive electronics. Almost certainly safer than plugging into shore power at a campground. I got this from an AI search: "Bluetti power stations are very safe for sensitive electronics. All Bluetti units use pure sine wave inverters. This mimics the clean, stable power of a standard wall outlet, preventing screen flickering, overheating, and data loss for devices like laptops, TVs, and CPAP machines... Avoid ECO Mode: If using a Bluetti solar generator, users on PowerEquipmentForum suggest turning off the "ECO mode" for the most stable and reliable power delivery to sensitive electronics."

A generator. There is another option in a pinch. You can use the Bypass switch on your EMS control panel (ours is in the "attic" over the bed). This will keep the EMS from blocking power from the "ungrounded" generator, but it will also remove all protection provided by the EMS. However, power from the Bluetti is already supposed to be clean, right?

Into an outlet in the Oliver or in the generator?

I needed to do so with my Champion generator.

I want to charge my Oliver with Blueitti (sp?) battery "solar generator". Is it correct that I need to plug a "ground neutral plug" in one of the Bluetti outlets to make it work correctly?

Have an elite1 with just a charger. House power cord came disconnected and drained AGM batter totally dead. Was able to recharge it with a commercial charger and now holds 12.5 volts but, I have no power for 12 volts items. I checked the power coming in from the battery and I get power to the bus bar and after that, I'm lost to where to trace for the lost of power. The charger is working because everything is working when useing 115 volts. Can anyone recommend where I should be looking for somekind of breaker I can't seem to find. No power going to the 12v fuse box either. Appreciate any help here....

Jd, thanks for the complimentary words as always! I mentioned the Auto Electric Specialist option because many folks may not know it’s a thing. It’s an ASE recognized field and most areas have them. We actually have three exclusive Auto Electric businesses here in small town Eureka. I also remember at least a couple of them when I lived in the Phoenix area near you. I don’t rule out that the truck has a problem, but I believe it’s the trailer because the dealer cleared the truck, and there were no other trouble codes. Wiring issues were found in the trailer and the repairs made the issue go away temporarily, so odds are that’s the source. Electrical problems can be very elusive, and often beyond DYI electric testing skills. My mention of a possible brake controller problem, or PWM digital interfaces, was merely meant to show that the problem could be almost anywhere, and one must consider that in their repair decisions. After several mechanics failed to find the problem, it’s reasonable to assume it’s not a simple problem to find. That’s why it would be “lucky” to find it with simple tests. My suggested test might find a ground problem, which would explain both the brakes and the flickering lights. However, intermittent problems, high resistance connections and shorts, degraded brake controllers, etc., could all cause similar symptoms, and they can be very hard to find. You'r right about the black wire, I must of had a brain embolism on that one. And I should clarify that the junction box is a likely place for problems to occur, but I’d probably start testing from the main ground bus under the dinette, and work backwards to the truck — only if there was high resistance or an open… keeping in mind that the brake circuit probably branches out separately from the junction box which further complicates testing. Also I didn’t mean to shut-down your emergency brake breakaway switch amperage test idea. However, it’s fed directly from the battery and a completely separate circuit from the TV. In fact, your low amperage readings didn’t compute with expected amperage for 4 brakes, so perhaps the switch only controls the brakes for one axle. Regardless, it’s doubtful that a problem in that circuit would show-up as a TV brake issue. Also, the hot side of the TV brake wire could create similar symptoms if there was a short to ground. That could be even more tricky to find. Some might use a Megger to test the wire insulation… which is over kill for 12v circuits. A jiggle test with a multimeter is the way to go, but it’s hit and miss. Anyway, see how quickly it gets complicated. I don’t like to throw out too much detailed information to confuse people, but I re-iterate that there’s more to it than folks might realize, and that’s why there are so many auto electric specialist’s. Hope that clarifies things! Cheers! Geoff

Geoff, from what I've observed over the last couple years, you know more about electronics than most of us who posts on our Forum. There is electronics in brake controllers but NONE at all on the Oliver side brake wiring. I do not mean to offend either, but is there such a beast as an "Auto Electric Specialist?" Some believe in Bigfoot! 🤣 We don't have this kind of service in our area, so are you offering a solution? So, how does this point to a trailer wiring issue? Why not a bad ground or faulty controller on the truck side? Aren't you just guessing without at least touching the Oliver, running the most basic tests with multimeter or clamp ammeter in hand? The U-Haul rental idea was a simple binary test to see if the error would occur towing another trailer. If the error could be reproduced it would eliminate the Oliver wiring as cause. Of course, the rental trailer must have brakes and 7-blade connection. Only one U-Haul counter person thought the 7-to-4-pin adapter would fit the need! 🤣 Also, in trailer wiring the white wire is ground, the black is 12V+ which is why in the picture the black is fused in the junction box. Am I wrong on this? If there is a ground issue on the Oliver side and there very well could be but we just don't know that. If it was my issue, I certainly wouldn't spend more money on specialists, just replace the ground. Attach a new ground wire at the junction box, test for continuity to the ground on the 7-blade plug, then run the new wire directly to the main ground bus under the rear dinette seat. This would eliminate trailer ground as cause in an hour with 10 ft of new wire, a simple solution. There are only 3 places where a connections, positive or ground, could be bad on the Oliver: 1) the 7-blade plug and wire harness back to the junction box, 2) the connections in the junction box and Oliver brake (blue+) and ground (white-) wiring from the junction box back, and 3) the wiring to the streetside brakes and through the axles to the curbside brakes. I would do some current and ground testing in these 3 areas and replace the most likely culprit. The entire trailer brake wiring, on the Oliver side, could be replaced in a day with $200 in parts. However, simple current and ground testing would determine one of these 3 areas to be at fault. It could be determined the factory brake controller is defective or has wiring issues. Four (4) GM dealers already struck out in finding a solution here, too much money spent. If true, I would bypass the factory system and install a reliable Tekonsha P3. There are only 4 wires in this controller harness, install new wire with +/- connected directly to the battery. Yeah, it's "piece-meal" but simple. But I can hardwire all of this at home (or any trailer shop) with hand tools and when done count on its reliability for many miles to come! 😎 I don't expect we'll agree on this one and that's cool. When I do yardwork, the weed-whacker is my tool of choice. I'm not planting a new flower bed. It's just not me. I know you like electronic switching systems, and you have demonstrated some great ones! Very cool, but some are a bit too complex for my liking. When I restore a used vehicle, like our Oliver, with factory or prior-owner aftermarket additions, once again I reach for the weed-whacker! Love your work, Geoff. 🤗

Those two were LOOSE when the “last” diesel auto mechanic opened that access panel. He tightened them. And he taped the wires underneath, near the hole in the axle. And he connected the ground wire on one of the truck batteries (all mentioned in my original post). The issue resolved for 3 days. Then driving over aged highway macadam and it started again. My brother mentioned the potential for the slightest bit of low voltage to mess with computer components in the truck. Today I reopened the vanity access panel, looked around, took photos, buttoned it up again. Didn’t change anything. Noticed there are actually two junction boxes in there, street side one much harder to access; I opened the curbside junction box. Those two black ground wires still looked tight. Tomorrow morning I move to new location (more rural). Confidence level is low. Two mechanics looked at the ground bus bar under the dinette, after I pointed out where it is located, but I don’t know if anyone was certain about which wires on it were/are associated with the 7-pin cable and/or the brake wiring. And I shared the wiring diagrams (such as they are) in the manual. One tested the individual elements of the 7 pin head (trailer side) and said he didn’t think the issue was there, it was functioning. Will do this in Cimarron, where my friend can help me.

I don’t want to offend anyone, but I have an entirely different view on this issue. It might be time to pull in the reins on the piece-meal fixes and take a fresh look. At lot of the advice provided is based on conventional auto electrics and trailer wiring. But things are much different with today's vehicles. There is changing technology with Pulse Width Modulation (PWM) switching, and the way it interfaces with modern LED lighting, and the low-to-ground switching of your Chevy that requires solid grounding. High resistance grounds and shorts can be hard to locate, and they can cause ultra low currents that will be detected by digital systems of new vehicles. These include grounds and shorts that might only appear under heavy loads, such as from your brakes. The heavy loads can cause insulation breakdown and arcing that might not be otherwise detected. The flickering lights you mentioned might be an artifact of your 2023 truck’s older PWM system and a separate issue, or it could be caused from a poor ground. It could also be caused from a failing brake controller for example. I agree that it’s most likely a trailer wiring issue, but I wouldn’t go rewiring the 7-pin or axle wiring just yet, or renting a u-haul with a 4-pin adapter because you will not get definitive answers. Unfortunately, new grommets will not help at this point either, the wires were already taped. The breakaway switch amperage will be ambiguous too. A direct short would smoke the wire, a high resistance short would be lost within the range of 9-12 amps for the 4 brake coils. But there are enough clues to point to a potential ground issue, so a ground check would a good start for most DIY folks. The trailer is grounded to the TV in 2-ways. Through the hitch ball, and via the 7-pin ground wire. The ball ground can be iffy, so the wire ground is important! You can see the black ground wires in your junction box picture, they are connected to studs that are grounded to the trailer chassis. A good place to start checking. Use a multimeter on ohm’s setting. Find a good ground on the TV for grounding one of the meter leads, and then start checking ground points on the trailer with the other lead while jiggling wires, including those on the axle. You will need two people, and maybe jumper cables to extend the test lead length. You should have fairly consistent low ohms readings. You might get lucky and find a loose connection. However, it sounds like various technicians have already checked for obvious problems, so at this point you are really in the territory of an Auto Electric specialist with proper logging instruments to test for intermittent problems and the ability to accurately trace circuit continuity. Auto electrics is a field of it’s own, and they are far more knowledgable that the dealers and regular mechanics. Just my two-cents. Good luck! Geoff

Or move the one out of my flattop cooking box to the truck cab 🙂. However, Rebecca would say I never met a tool that I didn't want two of, so.....(follows link). Agree on the Klein tools, can't count how many of their electrician screwdrivers I have. My electrical bag is pretty much all their stuff. Best recent thing, a USB meter when I was trying to figure out why the new charging port I put in the back was not working on my iPad. https://a.co/d/0i4XkaJ9 <- Shortened Amazon Link Love those - I have been considering taking off the plastic caps as I have lost two of the Oliver inserts and $50+ to put the company logo back on seems like money flowing the wrong way. Doesn't Oliver know I'm an influencer and they should give them to me for free? 🤣 🤣 🤣 Going to do one more day of spin test, give the lug nuts a torque, and happy Oliver camper our way back into Colorado today. Hopefully, all stays good till we get home, and there is nothing exciting to report tonight. Have an undercarriage day on my calendar before our next trip and will follow your video just to make sure everything is buttoned up before we head out for our next journey. Thanks for all the help!!

Another Chill Cube customer here however I've not installed it yet. I waited until the heat pump version came out to make my purchase. I didn't see the no drain system as a problem. I have a small window unit at my vacation home that uses the same method of throwing condensate on the condensing coil for additional evaporative cooling. It sounds like a waterfall when it starts but has never dripped. Now, I realize I'm making a big leap of faith the Cube will work the same but I'm not too worried if a little condensate flows off the trailer. We're still rocking lead acid batteries and don't have an inverter. My goal wasn't energy conservation as we're usually plugged in or occasionally on a small generator at lunch stops. My goal was quiet and humidity control in the trailer. My hope is when the Cube ramps down to a constant run state, it will achieve both. Fingers crossed

OTT told me the junction box was located here. Are you saying that this is not correct? Is there a second junction box not visible in this photo? (Reminder: I am checking in only periodically from my phone, as I don’t have WiFi in camp.)

Doesn't matter. Your mechanic thought this was the correct junction box and all the right colors are there for a trailer wire harness. This is referring to my comment on the black wire. The black provides constant 12V positive. In a cargo trailer that has no batteries it's used to power interior lights from the TV battery. In the Oliver and perhaps other travel trailers it uses the truck batteries to charge the house batteries. OTT disconnects it when installing LiFePO4 batteries. I believe it's a dumb and perhaps dangerous practice since a light gauge wire should never be used for this purpose. Anyway, this is not your issue. The only thing that connects power from your TV brake controller to your TT brakes is the blue wire. Just check to see if the blue wire connection tight. No, the Amazon link you provided has both male and female ends, its listyed as an extension cord. If you want to replace the male end, head only, get something like this. If the issue is at the truck to trailer connection only then this is the easiest route. Only takes an hour to replace this, Amazon.com: MECMO RV 7 Pin Trailer Plug Splice-in Replacement Trailer Side Male End 7 Way Round RV-Style Trailer Light Wiring Harness Connector, Heavy Duty 7 Prong Trailer Wiring Tow Plug for RV Boat Trailer : Automotive I like the idea of this one since it has a waterproof cable gland built into it, but it would be too long to fit on my truck. Amazon.com: Oyviny RV 7 Pin Trailer Plug with IP68 Waterproof Seal, Detachable 7 Way Round RV-Style Trailer Side Connector 7 Point Trailer Wiring Plug : Automotive If you need to replace the entire cable from the male 7-blade connector all the way back to your junction box under the vanity, you need something like this: Amazon.com: CheeMuii 7 Way Trailer Cord Heavy Duty 8 FT Trailer Wiring Harness Kit 7 Pin Trailer Plug Inline Wire Harness Cable for Trailers RVs Campers : Automotive Amazon links are to show examples. I'm not suggested these products specifically. No way you need a GM part and the picture of a part description you showed above is a combo 7-pin and 4-pin unit (4-pin for little trailers without brakes). You asked RE the clamp ammeter? I purchased a more expensive Klein product, their rugged version, but any will do just as long as it reads AC/DC, for the 120VAC systems and 12VDC systems we have on the Oliver. This one looks decent. Amazon.com: Klein Tools CL120 Digital Clamp Meter, Auto-Ranging 400 Amp AC, AC/DC Voltage, Resistance, Continuity, Non-Contact Voltage Tester Detection : Industrial & Scientific

Hey Gang, It's past time to retire the Penguin AC for something quieter and more suited to our eventual upgrade to a 600ah Lithium system. I know we have owners with the Truma, Houghton, and dometic freshjet 3 series. (Thanks to Roadlotus for her write up on the FJ3) I am leaning toward the new Dometic Freshjet 4 or 5 series. Reasons include: A) Quieter than the penguin (what isn't) B) would be easy to fit into the existing structure C) Service almost anywhere D) Has iphone app control as well as the Air Distribution Box control and E) Should be energy efficient enough to allow a few hours operation on a 600 ah system. I was considering the Furrion Chillcube but the possibility of condensate overrunning the pan down the side of the trailer is a deal killer. Just wanted to ask what I might not be considering on the above list OR if there is an outlier that is not on my Radar. TIY, Scotty

I need to hit the road so don't have a lot of time to respond here, but will try to answer some of your questions. My photo of the junction box was made in a hurry, leaning over the mechanic's shoulder; didn't see exactly what he did to fix it (wishing I had inspected before he buttoned it up). When I open it back up (likely at Lake Catherine SP) I will take more photos. I don't know what that means. Many times, I have checked my lights by jumping in and out of the vehicle. Then I discovered the "Test Lights" function on the TV center console (how convenient!) and all lights function. A few times I have had someone around to just walk behind while I engage breaks, backup, running and signals and all lights seem to work all the time. I haven't seen any malfunction of the lights on TV or TT *** EXCEPT!! Shoot -- Did I fail to mention that when the TT is connected by 7-pin cable, even when the TV is turned off, the trailer lights SOMETIMES flicker? I made a video of that; sorry if I failed to mention it before. It stops when I use the key fob and LOCK the truck. One guy said it's just low power to features (like the lights for seeing the ground at night), other guys said it was something wrong. I described it as looking like a SHORT IN THE WIRING. *** ... so besides that detail, the only malfunction I have experienced (beyond the warning lights on dash) has been intermittent NO BRAKES -- I test this using the Brake Gain Control on the center console at low speed; it also brings up information on the driver dash location that shows +2.5 or +3.0 etc -- when the brakes are not functioning that information show dashed lines in lieu of the moving blue bar on the indicator (brought to us by human factors engineering, right? so we humans can trust that something is happening there, but not actually connected in any mechanical way). I am learning to feel whether the brakes are working or not. Quite a few times, they start out not working and then they kick in. It seems to be related to vibration; a lot of times the warning lights begin after I have come to a full stop (traffic light, railroad crossing) and then I start out again and they start dinging away. I have spare wago connectors (recommended for my tool kit by Mothership) but no butt connectors, on crimping tool. I will order a new 7 pin connector. ** somewhere online Chevy says to "be certain to use the correct 7 pin connector" for this vehicle. When I asked the dealership, they kept telling me they don't sell those. I said, I want the part number of the one installed by factory on my truck so I can find correct matching end; it took them 10 minutes to understand me. I don't know how important that is -- Non-Chevy people (including OTT) say it doesn't matter, but I wonder about the control modules and how persnickety they are ** HOWEVER, since my Oliver operated without a hitch for three years, I figure whatever OTT installed was fine. (haha pun intended) I agree. Nothing worse than a ghost. I plan to do the U-Haul test. Might not even need to leave their parking lot, but I hope to get some sightseeing in while there (if I can manage working around the deluge that is coming). I will also look for an ammeter; it might also be useful to me for radio work. There seem to be quite a few different types, so if you can, recommend some minimum qualities (clamp-on, I see). Will order this. I can ship to my friend (fellow Oliver owner) in Cimarron. Gotta go. Thanks to all for the continuing help.

Boudicca: JD is a outstanding standup guy. Comes across some times a bit gruff (Don't we all?), but is pure of heart and giving to a fault. And Chris can sure cook up a wonderfull mountain of pasta as well. I went thru the same process as you, but had the tools and past knowledge to get to the bottom of it. For grins I would suggest you purchase a new seven pin plug for spare parts or use with JD. More than a few ownes like the one below. With or without the cable. It is one that John Davies suggested. If you have a spare few inches in your existing you could just get the 7-pin end. I had those inches and did just the end. Next time I'll have to get the full cable shown below. Amazon.com or Tractor Supply are both good sources for a lot of what we need. The cable connections are easy, getting the "Right" wire into the proper peg of the cord is complex. Having the same color to color at the box makes life a lot easier. Good luck. GJ

You are correct. I know nothing. My original post includes the fact that 3 separate issues were found and corrected by the last mechanic involving both truck and trailer -- and the fact that the warning lights disappeared and my trailer brakes worked for 3 solid days. Maybe you didn't see that part of the post -- or maybe you have concluded that none of those 3 things contributed to the issues? I'm suspecting that the wires behind the vanity may have worked loose again, as I was traveling. I cannot be certain that any of these issues were even partly the cause of the warning lights or partly the cause of the intermittent loss of the trailer brakes. I'm going to remove that vanity panel again, and take a look at the junction box. And when I get to Lake Catherine SP, I will see if I can rent a U-Haul trailer in Hot Springs. It looks like one of them is open on Sunday and Monday. I will let you know the result.

Yes. I certainly did. And Yes it is my Oliver. And yes I love my Oliver. I'm trying to take care of her. There was a problem with the truck AND with the trailer. I wish I were an expert mechanic, but I'm not. I wish I had more space for tools, but I don't. I appreciate your posts -- they are usually very informative. I don't own the equipment, but I am trying to learn, and I lean on the forum members who have the expertise and/or experience to help me. I bought a caliper last year, but it wasn't very helpful to me trying to measure the size of that hole in the axle to figure out what size grommet I need, because the wires don't allow me to insert it fully. hahaha -- more wasted money, perhaps. Service Dept couldn't / wouldn't give me a clue. So I ordered a box of 200 grommets off Amazon that are shipping to New Mexico where I hope to make progress on this thing. Unfortunately, that is the way this issue has gone for me. If I knew a lot more about these systems, I might not have been taken advantage of by lazy or incompetent people. What to do? Learn. I'm learning.

Wow, so many variables and it's more difficult when you have to count on service technicians, to whom are not all created equal. Yes, all 7-pin cables are the same. And yes, you can replace male head only (OTT is not always right). GJ did his and I did mine, been fine for 2 years. Changing out the whole cable is a bit of work. On my hull it's connected under the front dinette, past the wastewater plumbing (see pic). But who knows on yours since OTT hires random installers year-to year. In the picture you showed of a residential junction box, I don't see the trailer cable, the large black coupler cable, spliced down like you see in my picture. If you want to be absolutely certain whether your issue is the truck or trailer, take your truck to U-Haul and rent the cheapest trailer with a 7-pin connector! There is a lot less liability in doing this than borrowing a friend's truck or trailer, and less money than an hour of labor, shop rate at the Stealership! 🤣 See if you get the error message when towing the U-Haul trailer. The logic is binary. If it still shows the error, then it's the truck. Tow the trailer long enough and if it doesn't display the error code, then you have a wiring problem with your Oliver. So, if it's the Oliver, the next thing I would do is to test the brakes. Pull the pin on the emergency brake switch (the little cable you connect when hitching). Then take a clamp ammeter to the streetside, under the wheel well where you see two wires coming out of the hull, going to the brakes. Clamp onto only one wire, either wire of the pair. The ammeter should read about 6A on both sides (front and back axles). If it does, then all your brake wiring is good, so you can rule that out. (Don't forget to replace the safety brake pin when done.) If this test fails, then you have wiring issues at the axles, but don't waste time there unless you must. If the above test is positive, then connect the 7-pin coupler to your truck and run the same test. If it tests bad, then the brake wiring from the coupler back is bad (open) somewhere. Your next step would be to replace the 7-pin male on the Oliver. This will likely fix any Oliver-side issues. You don't really want to replace the entire cable unless you have too and OTT would likely charge a fortune to do this job. If towing the U-Haul trailer showed an error message, then it's your truck. What a shame 4 GM dealers cannot properly troubleshoot and fix the products they sell. If it was me, in a heartbeat I would disable the factory brake controller. Pull the fuses for it, buy an aftermarket Tekonsha controller and run new wiring to the female 7-pin outlet on your rear bumper (this is what I did from the start, since my older truck does not have a factory controller). This would cost about $200 in parts and likely 2 shop-hours to install, ANY trailer shop can do this, has the parts, maybe even the same U-Haul dealer could do it. I'd rather go to the dentist for a couple extractions than make a service appointment with an auto dealer, OMG! 🤣 And your story certainly shows why. Keep us posted and let me know if you have questions on anything I suggested. Best wishes, JD

Last September (2025) I mentioned this issue in another thread, and said I would post a new thread when I had it resolved. The thing is -- I don't have it resolved. I've been chasing this for months, unhappily. So I am going to share the saga, I will try to boil it down into concise bits, and maybe some of our more mechanically inclined members will have some ideas and suggestions. TV is a 2023 Chevy Silverado HD 2500 diesel truck. Oliver is a 2022 Elite 2, bought new from OTT. In early September 2025 I needed new tires. I dropped my truck off in the late afternoon at a reputable place in Pinedale WY. I asked them to check the spare while they were working on it. The following morning they called to inform me that my batteries were dead, so I needed new batteries as well. The next afternoon I picked up my truck; by the time I arrived back at camp, it was getting dark. I shut off the truck and discovered they had turned on my overhead lights and left them on (hence my dead batteries?)... In the morning I hooked up to tow to my next destination, and began getting alternating warning messages on my dashboard and center console: "Check Trailer Wiring" and "Trailer Brakes Connected" I pulled over (not 5 miles from camp) and checked my 7 pin connector; it looked clean, was firmly attached, my trailer lights all seemed to be working. But the messages continued. I could 'dismiss' these messages from the steering wheel, but they would pop back up immediately and they interrupted my view of my map on the center console, making it difficult to follow. In Denver CO, I had 10 days with family. I was convinced that something had happened to my wiring under the truck near the spare tire (wires, modules all in proximity.) I took my truck to two Chevy GM dealerships; neither had time for me nor would they allow me to bring the TT on site, but each ran their diagnostic and both came up with these history codes: B1325 Control Module Power Circuit Low Voltage, failure code 0x03; C1114 Trailer Brake Control Solenoid Valves Control Circuit, failure code 0x00; and P0562 Voltage Low, fail code 0x00. I call ahead to Amarillo TX dealership, explain the situation, guy on phone says he knows exactly what is wrong. Make appt. They don't do anything on Friday except change the oil; then the electrical guy is off for the weekend. I finally get the truck the next week, with this description: "Verified concern. Connected scan tool, found DTC C114 set in chassis control module, Checked trailer 7 pin connector for signs of corrosion, none found. Removed connector x188 at trailer receptacle and inspected for worn and pushed out pins, everything OK. Placed test lamp at pic c to ground and commanded low to high percentage with scan tool. Test lamp followed command from low intensity to high intensity change in bulb. Internal malfunction in k133 trailer brake control module. Replaced trailer brake control module and cleared DTC. Test drove to verify message did not appear on dash." (They did test drive the truck -- 18 miles worth.) $400 bill. I hooked up my Oliver to pull out, and the warnings continue. All during this time, my trailer lights and brakes seem to be working fine, but the warning messages continue. Fast forward to February. I hooked up for a short camping trip in Florida and the messages return. **I should note: I can't keep my OTT at home, and it's in a storage facility about 50 minutes north of my home. I'm not allowed to 'work' on it at the storage facility, and I can bring it on site to my neighborhood but only for a few days each year.** I call OTT Service dept on May 3, to check their calendar in case I need to come up before I head west for the summer; they have openings both spring and fall. I am determined to dog this thing and to try to resolve it without having to tow 900 miles to Hohenwald before my trip west. I have now taken the truck to 4 dealerships. They all say, "It's the trailer." I take my truck to an independent mechanic and he says, "It's the truck, but the modules should be under warranty, so go back to the dealer for this." Just to be sure, I find a Mobile RV Tech, tow the OTT to my neighborhood for one night, have him do his service (everything checks out fine on OTT, all working, but he finds something loose under the truck and the messages go away. But then they came back. This is exhausting. May 2026 -- Issue was still there, and now my trailer brakes aren't working. That is a new symptom. I say not working, but it was really intermittent; I could test with the gain control on center console and sometimes working, sometimes not. June 3, 2026 -- Back to dealer (45 minutes north of me), "It's the trailer." This time they let me bring OTT in tow; but they still say, "It's the trailer." A friend suggested another independent diesel mechanic that happens to be near the dealer. From the dealership I towed OTT to Elite Diesel in North Fort Myers, it's 3:30pm. They make a cursory review for about an hour, and say they believe it's the truck. June 4th, 2026 -- At this point, I am nearing departure date, so I haul trailer home, take truck back the next morning, get a ride home. Within 30 minutes they call me, "Can you tell us why your left side truck battery ground wire isn't connected? It still has the black cap on the end that it's shipped with, the cap on end of ground cable was never removed from the cable." (I've made 5 visits to Chevy dealerships citing need for regular service AND this electrical issue and NONE of them noticed this?) My new mechanic thinks this has solved the issue. I get ride back up (45 min), retrieve the truck, drive home (45 min), connect the trailer, issue still there. I tow the truck and trailer both back to independent diesel mechanic (45 min). I have work I need to do on my Oliver, so the mechanic agrees to let me do my work there (greasing my zerks in his parking lot) while they disassemble the spare tire, remove modules, check wiring in back of truck..... Now they are thinking something must be amiss in the trailer wiring. They don't stock that cable, so I might need to order one. I call OTT Service to inquire about what model or brand Oliver uses, since I've read that they are not all alike; Mike says he can't help me, transfers me to Tech Support. Jerry at OTT Tech Support talks to me about the 7 pin cable. He says the 7 pin cables are really the same (but Chevy Service Manual warns to use the "right one" to correctly operate the Chevy.) Jerry gives me some solid advice -- don't let them cut the head off the 7 pin connector; if head needs replacing, take it back to the junction box under the vanity, and other tips. I have no idea about this junction box; I can't find it in my manual or wiring diagrams, but I'm not a mechanic or electrical engineer. Jerry sends me a series of photos that show the route of the 7 pin cable in the trailer to a junction box inside the vanity cabinet. (see below) He says "if it has to go farther back from there, it's a really big job." (Oh boy.) My mechanic removed the vanity panel -- immediately saw two wire connections are loose though still have the nuts on the connection (below). ** I need to find the correct caulk (and thanks again to Jerry for providing the name of it) Silicone: ASI 335 Advanced Adhesion 100% Neutral Cure RTV Silicone, WHITE. Until that is fixed, I won't be using my shower, since it's open to this electrical junction box.** He tightened that down. Then he tried to find the rest of the wire, crawls under the trailer, sees wiring going into the street-side front axle where the insulation has been rubbed off. I am dumbfounded, so I wriggle under there, stick my head around the corner; these are really small wires, going through a hole in metal without any protection; they rub on that hole in the metal axle, and I see there is no grommet on the hole. This doesn't seem right to me. He wrapped it with electrician's tape. I drove around, and the issue had cleared up. I drove around some more. No warning messages. I had not crawled all the way under my Oliver before, though I have been greasing my zerks regularly; I grease the zerks from the side, not from below. I gave my phone to the mechanic and he snapped a couple of photos that I shared with Jerry, before he put the tape on. I was ecstatic, and so happy that with 3 distinct wiring issues this mechanic was willing to dog it, find them and deal with them. And THANK YOU JERRY. This is June 4th. My reservations are all in place and I depart early on June 8th. Yesterday June 10th, I called OTT Service again to inquire about whether there should be a grommet on that hole, and if so what size or could they ship them to me? Mike says he doesn't know if there should be a grommet, doesn't know the size and doesn't sell parts; transfers me straight to Tech Support. I talk to Jerry -- my hero -- and I send Jerry the photo from my mechanic before it had electrical tape on it. I had already purchased some Liquid Tape, extra electrician's tape and a box of Wire Conduit (that black plastic sleeve that is used all over the OTT). At that point in time, I was not getting the warning messages any more, but I was not entirely convinced that the tape on the wires would hold up to thousands of miles of travel. Jerry encouraged me to keep my eye on things, and I could get it repaired during my scheduled service in October on my way to the rally before I go back home to sw Florida. Don't you know it, less than an hour later, the messages came back. My trailer brakes seem to be working, as well as my lights, but it's very disconcerting. I found a Walmart parking lot and spent about an hour crawling around under my OTT. I applied more tape, put on a piece of wire conduit (sleeve) and inspected the other 3 axles. (below - you can see OLD piece of sleeve on far right side, and my new piece of sleeve, and you can see Mechanic's tape and my additional tape which is shiny and not dusty.) Additional tape and new conduit sleeve (above) on the street-side front that the Mechanic repaired. Other axels -- I added tape to one, shoved the grommet back into the hole on another (below). PHOTOGRAPHS & CREDITS: Wiring into axle (2 photos by Elite Diesel in North Ft Myers); Routing of 7 pin cable (5 photos by Jerry OTT Tech Support); the rest are my own photos, including my junction box with loose connections and my wire at axle with question about missing grommet (2 photos I sent to OTT); and then my 'discovery' of the grommets on the other 3 axles yesterday. The warning messages continue though they are sporadic. SO FAR the brakes are working (tested by using the gain control on my center console, when traveling slow speed). I'm inclined to keep going on my travels. I have an appointment with OTT Service in October. But I am interested in any additional input, and -- if for no other purpose -- I submit this for others who might have to figure out where that 7 pin cable goes and possible places to look. *I did try to search for other threads about this, but found none. I feel certain I've seen some comments about "usually trailer ground wire issue" but didn't find it. Thanks to all who have been in touch, and especially JERRY at OTT Tech Support for his kind and timely service. *** Please note: my wifi connection is via starlink and might be sporadic, and only when I'm not traveling. ***