All of the sudden on my 1992 F150 5.0 My brake lights went and quite on me. I have tail lights, But when I push on the brake pedal no brake lights. Fuses are all good checked them out. I am getting power down to the brake pedal where it plugs into some sort of switch on the brake pedal. could that switch or relay or breaker or what ever it is be bad???? I have also traced all the wires and can find nothing bad with them. I just don't have any power back to brake lights when pedal is pushed. I hope someone can help on this problem
thanks

 

That switch is the brake light switch and it is the most likely source of the trouble. You could pull the plug at that switch and try jumpering from the hot side to the other side --and if the brake lights come on--then this would verify that the switch is bad .If you have cruise control--that switch would also turn off the cruise.

 

Sorry I forgot to tell you that I tried that and still no brake lights. All fuses are good i rechecked them a couple times. any other suggestions??????????

 

If you have power going into the switch and jumpered around it and still dont have brake lights--I would suspect that there is a open fuse or less likely--open filament in the taillight/brake light bulbs. Are you sure that you jumpered around the brakelight switch?? Isnt there more than two leads going into the switch??

Check you owner's manual and see if the brake lights are protected by a fuse and what fuse it is.Then check that fuse and see if it is open.I know that you have already checked the fuses--but replace the brake light fuse anyhow--it is possible that there is corrosion on it.

I dont have a wiring diagram --and it may be that battery wouldnt be standing on the brakelight switch if the fuse was open.And this trouble could be caused by a bad ground on the brakelight circuit.But you said that the taillights work fine--and I would suspect that the taillights and the brakelights would have the same common ground.

Look and check any wiring connectors that run from the taillight assemby back to the cab for battery when the brakelight switch is jumpered..

But first--I would check the brakelight bulbs and check for battery at the taillight assembly--with the switch jumpered/closed and then work your way back towards the cab and brakelight switch.

Does your truck have a trailer wiring connector?

 

I had a inline adapter plug hooked into the tail lights. I eliminated it thinking it was the problem. I will check and change the fuse for teh brake light and try jumping across the brake switch again I believe your right on the switch being more than 2 leads. Thanks for your help, i see what happens tomorrow with your suggestions.