No brake lights

[patchesmcgee]

I jave a 81k 10. My tail lights and blinkers work, my brake lights do not. I have checked fuses and replaced the brake switch. What else could it be?

 

[fast 99]

Check power on brake switch when pedal is depressed and not. If no power head towards the fuse block. If powered other side will go to turn signal switch, then to the rear. Trace the power to signal switch. If power is present, my guess is an open circuit from brake light switch to signal switch or a bad signal switch. Reason signal switch enters into this is it opens the circuit [blinks] when brake pedal is depressed, and signals are on.

 

[Matt69olds]

Push and pull the hazard light button on column a few times, see if that changes anything.

Still no brake lights? Find the brake switch, check for power on the orange wire. If it has power, push the brake pedal, check for power on the WHITE wire. No power, replace the switch or make sure it’s adjusted correctly.

If you have power on the switch wire, find the turnsignal switch connector at the base of the steering column. Find the white wire in that connector, push the brake pedal and check for power on the white wire. No power? You have an open circuit somewhere between the brake switch and the turnsignal connector. Look for a stupid scotch lock connector for a brake controller, more than likely the scotch lock cut the wire.

If you have power on the white wire with the pedal pushed, find the yellow and green wires of the turn signal connector. While pushing the pedal, check for power on both of those wires. If not, replace the turn signal switch.

 

[Nodakr68]

So I have almost the exact same thing going on, and mine is an ‘81 K30.

I have one remaining bugaboo…..no tail lights or brake lights. Here’s whats weird….I can have a signal light on, or hazards on and they are flashing as should…..but I pull the headlight switch on, and the turn or hazards go dead.

Without signal or hazards on, and I pull the head light switch, still no tail lights or brake lights, but I do observe a soft glow coming from the right signal indicator in the dash ?! Kill the headlights and that soft glow goes away. So I assume I can dedicate my troubleshooting to the right hand side ?

I did check the brake pedal switch. With it unplugged, I have power to both the orange and white…..is that right ? Plugged in, there is only power on the orange…..push the brake pedal, and there’s then power on the white…..any thoughts ?

I already replaced the column ignition switch and headlight switch….what next ?

 

[Turbo4whl]

I already replaced the column ignition switch and headlight switch….what next ?

What's next, check the truck bed for a ground. No ground, bolt a wire from the bed to the frame.

 

[PrairieDrifter]

So I have almost the exact same thing going on, and mine is an ‘81 K30.

I have one remaining bugaboo…..no tail lights or brake lights. Here’s whats weird….I can have a signal light on, or hazards on and they are flashing as should…..but I pull the headlight switch on, and the turn or hazards go dead.

Without signal or hazards on, and I pull the head light switch, still no tail lights or brake lights, but I do observe a soft glow coming from the right signal indicator in the dash ?! Kill the headlights and that soft glow goes away. So I assume I can dedicate my troubleshooting to the right hand side ?

I did check the brake pedal switch. With it unplugged, I have power to both the orange and white…..is that right ? Plugged in, there is only power on the orange…..push the brake pedal, and there’s then power on the white…..any thoughts ?

I already replaced the column ignition switch and headlight switch….what next ?

Check ALL bulbs and grounds. Even the tiny little marker bulbs. When these trucks don't have good grounds they act really strange, have really strange problems.

I had one of those small marker bulbs cause a brake light to not work on the opposite side and I think a signal on the dash was always on.

 

[Dejure]

On grounds, mine is a 78, but there is a ground inside the driver's side rear fender.

 

[Turbo4whl]

On grounds, mine is a 78, but there is a ground inside the driver's side rear fender.

Yes they all have a ground from the lamp housing to the truck bed. Issue is the bed is bolted on the frame and rust forms. The bed can loose it's ground connection to the frame. Seen it happen more than once. Will drive you crazy with what will light up the wrong time.

If your truck has a ground wire from the bed to the frame, someone added it.

 

[Dejure]

Probably one of the most mentioned issues-solutions on this site.

 

[Nodakr68]

Just wanted to thank everyone, your help has been incredible. I started by replacing all side marker bulb sockets, corroded or not, and boom, I have brake lights again !! Thats huge for me.

There is one badly corroded front signal light socket, and one rear…..I plan on replacing those tomorrow.

Its a head scratcher to me, how the side marker lights can raise so much heck…..they shoulda been on their own circuit.

Today was a good day !! Thanks again !!

 

[PrairieDrifter]

Just wanted to thank everyone, your help has been incredible. I started by replacing all side marker bulb sockets, corroded or not, and boom, I have brake lights again !! Thats huge for me.

There is one badly corroded from signal light socket, and one rear…..I plan on replacing those tomorrow.

Its a head scratcher to me, how the side marker lights can raise so much heck…..they shoulda been on their own circuit.

Today was a good day !! Thanks again !!

It's like the trucks just want you to go to the basics. Bulbs and grounds will cause all sorts of stupid weird crap where if most "techs" today had to deal with stuff like that they'd lose their frickin minds.

If the lights are doing weird stuff on these trucks. Don't go chasing voltages through harnesses, visually inspect them for sure, but don't be ohming out every single wire and crap like that.

Check bulbs, grounds, and connectors. I hate to say throw parts at stuff but if a bulb looks suspicious don't be afraid to at least try replacing it.

 

[Nodakr68]

And thats my problem, I’m a field tech, for oil and gas. I live by P&IDs……but with my squarebody projects, I almost have to think backwards/outside the box.

 

[Dejure]

AND invest in dielectric grease to keep the oxygen off the contact surfaces (both the little soldered tip of bulbs and the large, negative base), on cleaned up grounds. . . ., just like you do on your battery.