# '05 F350 Trailer Brake Controller (TBC Fault)



## dpewitt (Oct 26, 2007)

I have an F350 Diesel and the TBC (Trailer Brake Controller) is driving me crazy. It "beeps" then says "trailer disconnected" followed by another "beep" then "TBC Fault". This is whether I am towing a boat trailer or not. I do not have electronic brakes on the boat trailer anymore so I do not need this feature. The problem is that it BEEPS at LEAST ONCE A MINUTE!!! You can imagine how crazy this will make you. 

I would like to try fixing it somehow myself before taking it to a dealership to diagnose and repair. Any ideas on how to make this go away? I do not see any visible damage to the wiring. thanks,


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## Tuna Man (Oct 2, 2007)

Sounds like the Voltage supplied (gain) to the unit may be off and needs re-calibration. Check all lights, as this can be a problem. Voltage is supplied to the unit (for breaking) 100% of the time, not just when used. When used more voltage is supplied. The plug draws voltage even at rest when plug in, but I don't know if it is when no trailer is hooked up. Since you have this problem when either trailer or not is hooked up, I suspect the module or a short in the wiring somewhere.


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## dpewitt (Oct 26, 2007)

This happens whether a trailer is hooked up or not, most of the time not in my case. I also checked all fuses under the kick plate and in the engine compartment and they both look good. All running lights and trailer lights work as well. I would be happy with just disabling it for now to get rid of the beep. I do not plan on towing a trailer that will have electronic brakes anyway.


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## Tuna Man (Oct 2, 2007)

To totally disengage the unit, cut/remove the RED (going to the brake unit) wire on the brake switch located on the brake peddle arm. Be careful that you get the right wire as it also has a wire for your brake lights. Let me see if I can find a picture for you.










I think I'd do both the *Red* and *Blue* arrow. But at least the *RED*. Do RED first and see if that corrects your problem.


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## cape horn 24 (Sep 29, 2007)

I know he said a F350, so if it's an after market controller does it hook up to panel located on thefire wall near the brake pedal, as mine does on a 2500 chevy? If so could you just unplug the entire unit and remove it orreplace it if needed? When mine went bad, I unplugged the bad one then plugged in the new one and used same holes under dash for the unit.

BA


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## FlounderAssassin (Sep 28, 2007)

i believe on an 05 they had the optional factory break controler...which from what he is saying it sounds like what he has. there should be a fuse under the hood that you can remove and that will kill power to the controler there for not letting it beep anymore. if it is an aftermarket break controler then its plug and play on that truck so just follow the wires to where they plug in at the junction box under the dash and you will no longer have any trouble with it. if you need further helo with it (expically if it is an aftermarket unit) give the guys at A-1 a call. they will be able to get you fixed up. 968-4400


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