Tow Vehicle Brake Lights Only Work With Manual Override On Brake Controller

Question:

I have a 1994 f-250 the controller has work find for a little over a year. then resently I went to drive my truck without the trailer it started find but would not release the shift interlock and the brake light werent working.after a lot trouble shooting I found that if I slid the over ride lever the brake lights came on and truck shifted out of park then I disconnected the unit from the harness and ever thing work find brake lights work shift out of park. All the hook up look good and I keep the truck in the garage when not being use so I dont think its a corrosion problem.

asked by: Ken M

Expert Reply:

That is certainly an odd issue you are having with your brake controller but I can't say I know exactly what problem is causing this. The only thing I can think of is possibly a fault on the stop light switch circuit connection or a bad stop light switch all together. I know you said you checked the connections but what I recommend you do is make a new splice into the stop light switch circuit which is the red wire coming from the back of the brake controller. In order to do this you will want to use a quick-splice connector, part # SWC502905-1.

Also, I did not catch what brake controller you were using but most will illuminate the brake light circuit on the vehicle with the manual override so this much sounds normal. Again, the only reason I can think of if they are not working with the vehicle's brake pedal is a fault on the stop light switch circuit connection or a bad stop light switch.

If the new stop light switch connection does not fix your issue then it would be best for you to take the truck into a local repair center.

expert reply by: Conner L