Troubleshooting Brakes and Brake Lights Not Working on Trailer with Freightliner

Question:

I have a 2001 fld112 single axle Freightliner air ride pulling a 2014 Kaufman electric brake trailer. My brake lights are not working Ive also noticed that my brake control on my Dash has quit. The male and female end of my trailer plug in we rebuilt or simply put it has new ends cuz it was green and falling apart. Recently rewired the entire trailer. Signals work running lights work. No brake lights it appears the electric brakes are working. All lights and brakes on my air brake tractor are fine. What do you think the problem is

asked by: Ian

Expert Reply:

If both the trailer brakes and brake lights aren't engaging when hooked up to your 2001 Freightliner the first thing, I recommend doing is testing the wiring connector on the truck with a circuit tester like # PTW2993. Test the brake output and brake light circuits on the connector with those functions activated to see if you get power there. If you aren't getting any power, then you at least know that the issue is somewhere on the Freightliner and not the trailer.

You will then want to inspect the connector itself for any signs of corrosion or debris built-up around the pins, cleaning out as needed.

I am not sure what type of brake controller you have installed on the Freightliner, but I recommend checking its wiring and connections for any frayed or exposed areas that might be causing a short that need to be replaced.

If you did get power when testing the connector on the Freightliner, then the issue is actually on the trailer. Since you recently re-wired everything, you will want to make sure that the correct connections were made at the connector so that it matches up to the Freightliner. Check to make sure the electric brake assemblies are securely grounded to a clean bare metal surface. Do the same with the brake light assemblies. Also inspect the connector on the trailer for any debris or corrosion like you did on the Freightliner.

If you are still having this issue, please let me know and we can continue to troubleshoot.

expert reply by: Chris R