Troubleshooting Trailer Brakes on Tandem Axle Trailer With One Assembly Issue

Question:

I have a tandem axel trailer, 3 out of the 4 breaks work, I have 6.3 volts at all breaks, just put on a new break assembly, that came with a new magnet, I’m testing off a battery charger and a tester, the tester is functional and works properly... can seem to figure this one out. .. please help

asked by: Jordan K

Expert Reply:

When testing your tandem axle trailer with brakes, you should first test your 5 o'clock pin on your 7-way while using the manual override slide. You should get 12V at that point. The manual override needs to be applied because proportional controllers need to sense movement for the brakes to apply a proportional amount of voltage for brake pressure.

If that checks out, then check your main trailer ground connection to make sure it is bare metal and free of debris or corrosion. Then inspect your brake output wiring to your magnets and make sure every magnet ground connection is bare metal to metal and free of corrosion. It sounds like you may have a wire short to that 4th assembly and if so replace wire with # 10-1-1 sold by the foot.

Finally, if you are still having issues, bench test each magnet using a multimeter like # PT89ZR. I've attached an article to assist with how to test them.

expert reply by: Jason S