Troubleshooting Electric Trailer Brakes

Updated 03/22/2019 | Published 03/21/2019

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Bulldog Winch Trailer Winch - Synthetic Rope - Hawse Fairlead - 7,800 lbs

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LCD Digital Circuit Tester

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Question:

Trailer bakes will not work after harness replacement and pin setup. Actions to date: New trailer controler, progressive red light indicates good signal Test/inspect all fuses in Ram truck. Bought 7 pin tester, plug it in and all lights work fine and trailer brakes signal works as normal. Still no brakes. Profile 2016 doudge ram and 23ft double axle E- brake design Keystone ultra lite year 2015 less than 5 K miles used. QUestion: I used grease on ball socket once very hard to get on truck ball. Do I need conductive grease or ?? Please advise. And Thank you.

asked by: Mark L

Expert Reply:

Troubleshooting electric trailer brakes is much easier if you disconnect the trailer plug from the truck and test each side separately. The process is not complicated and you need only a few items.

I suggest starting on the trailer. You'll just need a well-charged 12V battery (the one in the truck will work fine unless you happen to have a fully-charged spare one laying around), a standard set of jumper cables like # HMBC0860 and two short lengths of wire. You will connect the jumpers to the battery and to the two lengths of wire. Then apply these two wire leads to the contacts on the trailer plug, the ones shown in the photo I linked for you. You should hear the magnets humming.

If not, check that your re-wiring has the various circuits arranged according to the RV standard format shown in the linked article. It could just be a matter of an incorrect pin assignment when the re-wiring was done. If you apply the battery power to each contact on the trailer's plug you'll eventually find the brake circuit if it is not connected to the correct pin location in the photo. This testing process also allows you to test each trailer light circuit too and this is a good idea while you have the jumper cables connected.

If any trailer circuits do not work you'll want to trace their wires looking for worn or cracked insulation or spots where the wires may be rubbing on the frame or suspension components.

If the trailer behaves correctly with the direct battery power then get a circuit tester like # PTW2992 and move to the truck. Again please refer to the linked article to see how the circuits on a 7-way vehicle socket are arranged. Have a helper set the brake controller to maximum power and boost and apply the manual lever while you test the brake circuit on the truck.

If you get no signal there then you know the issue is on the truck. Please let me know the results of your trailer test and I can give you next steps if needed.

expert reply by: Adam R