Brake lights

[brentcovey]

My tail lights and turn signals work, but no brake lights. I replaced the brake light switch and tested it but still nothing. It's a 79 K20. Any ideas?

 

[ali_c20]

Check the fuse. If I recall right brake lights and emergency flasher share a fuse. Check if there is power to the switch. Check the switch, new parts are sold broken often these days . If you have done this and all is good you have to go through the whole circuit from begining to the end.

 

[WP29P4A]

Are you using a test light or meter to check for voltage? Does it have trailer wiring/plug/socket? It's common to have bad connections where people splice into the tail light wiring, for trailer lights.

 

[CheemsK1500]

Check the light sockets themselves. The plastic gets brittle and the metal contacts get bent. I've had to swap out many light sockets on trucks more than 2 decades old.

 

[fast 99]

Brake and tail share the same circuit. If the turn signals work the problem is up front. Turn signal circuit interrupts the brake circuit. That way the turn signals work with the brake pedal depressed, like at a traffic light. In other words power goes through the brake switch then to the turn signal circuit. Way to check, see if power is on both sides of the brake light switch with pedal depressed. If so, then follow it that power up the column to the turn signal switch. I would suspect the switch under steering wheel has an issue or the wire plug to the turn switch is fried. Those turn switches get loose or worn at the rivet hinge point opening the circuit.