Where is this breaker located?

[Jim and Frances]

Can anyone tell me where is breaker "B4"?   This is on a 2021 LE II.

Also, not sure what the "charge line" means. Is this the 12V charge line coming in from the tow vehicle?

Thanks for your help!

[jd1923]

@Jim and Frances, thanks for providing this picture, I had not seen it before.

I'd wish Oliver would not use "Loose fuses." Better to install a larger panel for all DC fuses, labeled and easily found in one location. They don't do this in automotive manufacturing. Instead modern automobiles have 2-3 fuse panels.

What is really troublesome is two fuses on the same circuit, though I have argued with others here to their value. IMO it's a bad design where you can check a fuse, find it's good and unbeknownst to you, they hid another fuse somewhere down the circuit.

I believe you are correct in that the "Charge Line" is the Black wire from the 7-pin hitch harness. The graphic shows the B4 location, meaning there should be a fuse up front likely outside under the doghouse. Your picture does not show the B5 location which I would guess is under the streetside bed where the charge line connects to the rear +bus.

So as I mentioned this line looks to be fused on both sides. BTW, Oliver disconnects this charge line for LiFePO4 installations. I believe the only valid purpose for the Black wire on this harness is for cargo trailers that do not onboard batteries needing 12V+ to power accessories, mainly interior lighting. Unless you're one of the cool guys who jump that line to power the trailer marker lights when off hitch. 🤣 

If you have the full PDF file of this graphic, could you please attach it here. I save every Oliver schematic and drawing that others have posted. Thanks

[Snackchaser]

@Jim and Frances, you are right, the charge line is from TV alternator (Pin-7 of the 7-Pin harness).  I'm not sure where that B4 breaker is, it looks like it must be under the bathroom sink or in the propane house.  B5 would be under the bed on the street side.

As JD noted, Pin-7 is not connected for lithium batteries.  This is because lithiums have specific charging parameters that are different from lead acid/AGM batteries, and they could be damaged by normal alternator charging.  So if you have factory lithiums, then you probably don't have the B4 and B5 breakers.

If your trailer came equipped with lead acid/AGM batteries, then Pin-7 is probably connected through the B4 an B5 breakers.  It’s a comparatively low amperage charge and not very efficient to charge the house batteries.  But any trailer with electric brakes must have a battery and Pin-7 charging, or equivalent, for the “breakaway brake switch,” which I believe is a DOT requirement.  

Two breakers are definitely needed because there is current potential at both ends of the this circuit, from the battery on one end, and from the alternator on the other end.  The breakers are polarized, meaning they only protect the wire on the “load” side of the breaker, and the “line” side is connected to the current potential.  So if you had only one breaker, it can only protect the circuit from the battery on one end, or the alternator on the other end. . . but not both. 

Now if a fuse was used, only one would be needed because they are not polarized.  But I'm not saying a fuse would be better because I fully believe Oliver observes sound electrical engineering practices and there is good reason to use breakers in this configuration and others.

Hope that helps explain things.  Cheers, Geoff

[Jim and Frances]

@jd1923 I've attached copies of the electrical pages for the 2021 LE2 from the Oliver manual...is this what you needed?

Thanks again for your and @Snackchaser's help!  I will do some more searching!

Electrical Pages from OTT-2021-Owners-Manual-compressed.pdf

[jd1923]

3 hours ago, Jim and Frances said:

I've attached copies of the electrical pages for the 2021 LE2 from the Oliver manual...is this what you needed?

Thank you Jim, yes this is great. Won't the same wirings for our hull, but the 2016 OTT User Manual did not have any of these drawings.

Looking at the full page, the B5 is under the curbside bed as Geoff and I expected. 

[Mike and Carol]

8 minutes ago, jd1923 said:

Won't the same wirings for our hull, but the 2016 OTT User Manual did not have any of these drawings.

We’ve had to figure out quite a bit over the years.  I’m glad documentation is now more complete.

[Jim and Frances]

23 minutes ago, jd1923 said:

Thank you Jim, yes this is great. Won't the same wirings for our hull, but the 2016 OTT User Manual did not have any of these drawings.

Looking at the full page, the B5 is under the curbside bed as Geoff and I expected. 

No prob....I've got the B5, it's the B4 I for which I am hunting.

[jd1923]

9 minutes ago, Jim and Frances said:

No prob....I've got the B5, it's the B4 I for which I am hunting.

You'll have to follow the 7-way connector cable, front to rear and see where they split the cable into the 7 separate wires, looking for the black wire.

Let us know on both ends, are they using fuses or breakers? I forget if there was anything under the streetside bed when I disconnected the black wire on ours 2 years ago. I insulated the end of that wire and tucked it away in a dry spot off the floor.

[Steph and Dud B]

10 hours ago, Snackchaser said:

electric brakes must have a battery and Pin-7 charging, or equivalent, for the “breakaway brake switch,” which I believe is a DOT requirement

The breakaway switch and battery are required, but not the charging. I had a car carrier trailer that only had a small sealed LA battery for the breakaway system, similar to one you'd find in commercial burglar alarm cabinets. The battery wasn't connected to the TV charging line. (Oddly, that line was used, but only for the interior lights.)

[Snackchaser]

3 hours ago, Steph and Dud B said:

The breakaway switch and battery are required, but not the charging. 

Yes it seems your right, the charging is desired, but it's not explicitly defined in the regs.  

Years ago when I used to tow a sizable boat into Canada, I was almost denied entry one year because they had just outlawed Surge brakes.  I had to replace the trailers surge coupler head with an Electric pump/hydraulic unit including a breakaway switch, battery, TV charging, and an electric brake controller.  It was a unique setup because you don't want to dip all electric brakes into water when launching a boat.  That expierience was burned permanently into my pocketbook and memory!  

Cheers!  Geoff

[jd1923]

4 hours ago, Steph and Dud B said:

The breakaway switch and battery are required

In 3 cargo trailers I’ve owned, the breakaway had its own small independent battery and the Black wire was used to power interior lights when hitched.