Electric brakes on trailer question:

[rbgarr]

I've got a round six-prong connection for the electric brakes and lights on my trailer, and a Tekonsha brake controller/adjuster under the dash. The trailer has never been submerged. For the first year ever in six when I hooked everything up to pull the boat out of storage, the trailer lights worked, but the 'telltale' light on the controller did not, and the brakes would lock up (electrically), preventing movement. When I disconnected the plug, the lights would not work (of course) but the trailer would roll freely. So when the trailer gets electricity the brakes lock up. I'm confused why this would happen.

I'm going to contact Triad (trailer mfgr) tomorrow to see if they can make any suggestions about what might be causing this, but thought I'd ask for ideas here in the meantime. :confused:

[mmd]

Sounds like a short somewhere in the system. Did you check the wires for abrasion along the trailer frame? Maybe check them for continuity with a multimeter.

[htom]

If it's been working for five years, then it must be a break or short somewhere. Well, it's possible that you had something done to the vehicle that managed to zap something in the car end of the circuitry, but I'd check all of the trailer wiring first, twice, before looking elsewhere.

[Gary E]

I would get out the multimeter and start checking to make sure the output of the controler is correct.

If the output of the controller is correct then the fault is in the trailer mounted unit.

If that is not correct, then disconect the power to the controler and you should be able to move the trailer.

G

[Del Lansing]

Anyone bump the controller out of level or mess with the sensitivity or gain controls?? Might just need re-tuning.

[Del Lansing]

It's been a few days but I found the schematic for my electric brakes. The controller sends constant 12V to the brakes, obviously that is there because your unit locks up. The controller modulates the brakes by switching the return line to ground. My best guess would be the return line either on the trailer or on the tow vehicle is shorted to ground. That would turn the brakes on hard and also cause the continuity light to not turn on. The trick is now to find which line is the return line and where it is shorted to chassis.