Trailer Brake & Parking assist fault

[dzimbric]

I keep getting a Trailer Brake Service fault, intermittently the fault clears and the brakes work. It’s really annoying when towing weight. I have replaced the brake control relay and the tail light circuit board and cleaned the connectors.
Is there another connector between the controller on the dash and the brake relay.
It happens with all of my trailers and even shows when no trailer is connected. I also have had the “Service Park Assist” fault for awhile but just ignore because I am normally pulling a trailer.

Any advice is appreciated.

 

[Chevy1925]

are you running a lift pump?

 

[2004LB7]

Behind the rear bumper is another connector. Mine was full of dirt and junk

 

[TheBac]

Moved to Towing Section.

 

[Ron Nielson]

When you say you are getting a 'fault', are you referring to a message on the DIC? Or a check engine light that has a DTC associated with it? or ?? And this is for your 2008 truck in your signature?

 

[dzimbric]

When you say you are getting a 'fault', are you referring to a message on the DIC? Or a check engine light that has a DTC associated with it? or ?? And this is for your 2008 truck in your signature?

It is for the vehicle in my sig line. I am getting “Service Trailer Brakes’ message on the DIC. I get it with and without the trailer being connected. I replaced the brake light circuit board located behind the bumper and the brake relay located next to the fuel tank on the frame. It may be a loose connection because it was coming back in today with no trailer connected when I would hit a bump.

Suggestions?

 

[dzimbric]

Behind the rear bumper is another connector. Mine was full of dirt and junk

I chaged it. No success.

 

[dzimbric]

are you running a lift pump?

No

 

[dzimbric]

Does anyone know what the module located next to the trailer brake relay does? It is mounted on the frame behind the fuel tank and has a weird plug that I can’t get apart. Also how do you get the plug off?

 

[JoshH]

Does anyone know what the module located next to the trailer brake relay does? It is mounted on the frame behind the fuel tank and has a weird plug that I can’t get apart. Also how do you get the plug off?

That is the trailer brake control module. I just changed it on my dad's 08 dually because he was having intermittent service trailer brake messages, and diagnostics indicated that it was the problem. The new one is still giving those messages though... I remember the plug being a pain, but I don't remember exactly how it unlatched.

 

[Ron Nielson]

A new trailer brake control module, which mounts right next to the trailer brake relay, must be programmed. A quick trip to the dealer, or independent garage, is in order. If the module was your problem, you may have a working, error free trailer braking system. If the problem lies elsewhere, you may still have problems.

 

[dzimbric]

Will this cause an intermittent fault or just make it not work? I am experiencing intermittent faults and have replaced both modules under the bed of the truck.