Brake light not working

[1Gordon1]

Can anybody help me figure what is happening with my 1970 Chevy C10 ? Had new turn signal switch installed, new rear wiring harness installed, new rear turn/brake light housings and everything was working. Had the truck painted and NOW everything works but the brake lights put a new brake light switch on and still no brakes. Turn signals, taillights, and flasher operate but no brake lights. Could there still be a ground problem even though turn and taillights work ?

[VetteVet]

Originally Posted by 1Gordon1

Can anybody help me figure what is happening with my 1970 Chevy C10 ? Had new turn signal switch installed, new rear wiring harness installed, new rear turn/brake light housings and everything was working. Had the truck painted and NOW everything works but the brake lights put a new brake light switch on and still no brakes. Turn signals, taillights, and flasher operate but no brake lights. Could there still be a ground problem even though turn and taillights work ?

There is a white wire from the brake light switch to the turn signal harness connector on the column. Check it for 12 volts with the brake pedal pushed.







If you get 12 volts then check the dark green and the yellow wires in the connector for 12 volts. These are the brake light wires. If you get the 12 volts, Then the turn signal switch is good and the problem is in the rear harness or at the rear lights. If your tail lights work then the grounds are good.
The turn signal wires are the same as the brake light wires.
Dark green is right turn/brake and yellow is left turn/brake light.
Since your turn lights work your wires are good to the rear and I suspect it's the turn signal switch.

[Stocker]

You're lucky, you just got advice from our resident electrical wizard.

Nothing I can add except to say welcome to the board!

[1Gordon1]

Thanks VetteVet and Stocker. What if I don’t get 12 volts when checking white wire leading from brake light switch to turn signal switch ? Does that mean turn signal switch is bad ?

[Stocker]

I may be mistaken, but it appears there should be 12V from a fuse through an orange wire to the brake light switch. Pressing the brake pedal will extend voltage to the white wire.
Hope this helps and that I'm not leading you down the rabbit hole.

Link to wiring diagram.... look on the right side of the drawing. https://www.google.com/imgres?imgurl...act=mrc&uact=8