Testing Emergency Break-Away Switch

[ScubaRx]

The other day I decided to see if my brakes needed adjusting and to test the emergency break-away switch on our trailer. I didn't have any reason to think it would not operate properly, but I figured knowing it would work would be better than finding out the hard way that it didn't. The trailer was not connected to the tow vehicle. It was plugged in to external power. I lowered the jacks on both sides until each tire could spin freely and pulled the switch pin. I then tried each tire and, to my surprise, they both still spun freely. No clicking, humming, no sound at all. My first thought was that, for some reason, it needed to be unplugged from the external power. No change. Next, I figured the switch or the wiring of said switch was somehow bad. I replaced the switch pin and checked the wires coming out of the switch. One wire showed 12 volts (this one apparently coming from the batteries) the other one was "dead" until the switch pin was pulled and then it too showed 12 volts. That proved that the switch itself was functional. I then found the blue wire inside the trailer that exits to the outside to attach to the brake drum on the street side. This wire tested hot when the switch pin was pulled, so I knew the wiring was good to that point. I then checked it outside the trailer at the drum and that tested hot also. Meanwhile, the wheels still spun.

 

So, what am I overlooking? Am I incorrect in my expectations? Could it be that the brakes only need adjusting? To the best of my knowledge the brakes have always worked properly thru the tow vehicle.

 

Any suggestions would be appreciated.

 

Thanks...

[SeaDawg]

Steve,

You may have a bad ground. Check the ground wire where it goes back to the bolt that is screwed thru the fiberglass shell and into the aluminum frame, near the wheel well hump, under the small dinette seat on the driver's side. Ours loosened up a couple times and only made only intermittent contact. Paul tightened it and cleaned the connections a couple times, but we finally just drilled a new hole drilled and installed a new bolt to maintain a good ground connection. We think that possibly there may have also been some corrosion/oxide in the original ground that prevented a good connection.

Our clue was also brake related, but different. We had an intermittent problem with the brake controller showing no connection on the panel as we were driving. Going over a bump up up a hill, we'd lose contact, then it would return on its own ...

 

Hope this helps.

 

Sherry

[bugeyedriver]

Steve,

 

I tested my trailer this morning under the same conditions as yours: disconnected from TV, plugged into shore power, weight off both rear wheels. Before the test, I confirmed both wheels turned freely, then I pulled the pin on the Tekonsha breakaway controller. Testing each side had the same results - very slight movement permitted, followed up by braking action. After putting the pin back in both wheels turned freely again.

 

I noted the wire to the breakaway box would not activate the pin at the full extension of my chain, so I lengthened the chain connection by one link and all was well. During towing, be sure the wire to the breakaway box is hooked to your TV, not the chain. (When I got mine from the factory, they had it connected to the chain, which wouldn't help if the chain somehow failed)

 

While cruising the internet on your dilemma I noted some folks activate the breakaway controller and then take a compass and move it near the brakes. If you note compass needle swings as you do this it shows you've got magnetic power at the brake.

[mountainborn]

Very good test techniques, you guys ! I usually check the brake controller in a WalMart parking lot, by manually activating it when slowly coasting, after the drakes bring us to a full stop, I then pull the pin and gently try to drive away. The brakes will be obvious so don't flat spot your tires by continuing to pull and sliding the trailer tires.

[mountainborn]

The manual application of the brakes will let you see how much current is being drawn or the number of the read out of the brake controller. This gives you some idea of how much you want to pre set your controller for, or how quick your trailer brakes come into play and how hard. Which is really the bottom line for all of us as we tow our trailers.

[ScubaRx]

Brakes Fixed!

 

The problem was simply that the brakes were not getting a ground when not hooked to the tow vehicle (I've yet to make sure the brakes work during tow, but I don't have any reason to think otherwise--but I will check.) Both drums are grounded with the same wire (goes across to the other side thru the axle) so when one worked they both did.

 

Sherry, you and Paul suggested it first. Thanks for everyone's help

 

Steve

[technomadia]

Just tested our emergency brakes, and they also seem not to be working.

 

I suspect it may be a grounding issue - I will report back when we figure it out.

 

- Chris