Trailer Brakes Dont Work w/2008 Silverado but Other Trailers Work and Other Trucks Work w/Trailer

Updated 07/27/2016 | Published 07/26/2016

Question:

I have two trailers that my 08 Duramax will not link to the breaks all other lights work, but an 03 Duramax, 11 Duramax, and a 15 Ford will connect. However my truck will link to other trailers with trailer breaks. I have right under 4 volts on the truck plug that fluctuates from 0-4. I have had the trailer grounded in multiple places. I cant figure out why I truck will not link. Thanks in advance.

asked by: Curt

Expert Reply:

It sounds like there is a short somewhere because you should not be getting fluctuating voltage readings. Usually this is caused by a dirty/corroded trailer connector and/or a loose wire. Make sure the truck and trailer side connectors are clean and free of corrosion inside where the wires attach and outside on the pins. While inside the connectors you can check for loose connections.

Every vehicle's tow package wiring is different and sometimes a trailer function will work with one truck and not another like in this case.

You can also test the brake controller and the trailer brake magnets (articles on these subjects linked for you) but since the trailer works fine with other trucks and the truck works fine with other trailers it seems unlikely that the brake controller or magnets are to blame.

expert reply by: Michael H