Blinker / Brake light issue
 

I put LED tail lights on my daughters 63 GMC. I did not have time to diagnose the problem and won’t be able to be with the truck until next week.

The blinkers and brake lights both do not work. The brake pedal switch is working properly just no lights in back. Power to the flasher when turn sig on left and also on right. I know I need to get an LED flasher, was thinking about a new blinker cancel and steering column wires.

Any thoughts ?

Re: Blinker / Brake light issue
 

check your connections under the steering column. The white wire on the end is the stop light wire. Disconnect the plug and put 12volts to the wire going to the rear and see if you have lights if so then it is in your column. if not it is in the harness to the rear. next to the white wire is a green wire. that is your right blinker. do the same thing . I believe if you figure out one blinker you will figure out the other. the blue wire is your left blinker. first make sure this connection is good on the plug. Good luck.

Re: Blinker / Brake light issue
 

Be aware that led have to have correct polarity.

Re: Blinker / Brake light issue
 

Jim is right...pos and neg...

Re: Blinker / Brake light issue
 

Thanks for posting, I just had a moment to look at the truck again

I unplugged the rear tail light harness in the cab and ran a jumper wire, the rear driving lights and both brake lights shine bright

I could only find a 1964 Chevy wire diagram and I am working on a 1963 GMC. I think I figured out the wire color differences and now have some questions

1) The white wire on Both pickups is the wire from the brake peddle switch. When peddle pushed the white wire is hot to the plug at the steering wheel to the blinker switch. When I run a jumper wire to the white on the blinker switch side of the plug I get no current on any wires coming back out of the steering column blinker switch (bad blinker switch ?)

2) When I heat up the yellow wire on the blinker switch in the steering column and excersize the turn signal lever I get current coming back down from the steering column blinker switch in the purple and pink wires. When the blinker switch is not excersized and in the middle position all wires have no charge. (Good blinker switch ?)

3) when I turn the key on and check for current in the plug from the fuse box I do not have current on any connectors in the plug. Should I have current in something feeding the steering wheel when the key is on ?

What tells the flasher to send the blinking signal up to the steering wheel blinker switch ?

Should I look at getting a new fuse panel under dash wiring kit ?

Anyone know where to get a 1963 GMC wiring diagram ?