Gentleman, I am new to the forum and have enjoyed reading many of the posts. Well I am having issues with my tail lights and brake lights when the head lights are on. I have spent 7 hours cleaning every ground and chasing the gremlins. This is what, I found that is staying consistant. When the bulbs are out the brown wire on both the left and right have power when the head lights are on. The yellow and green wires have power when the brakes are on. The weird thing is when you put the bulbs back in the lights will not come on at all with the head lights on with or without the brake applied. The very strange thing is the light housing has 11.5 volts on it on both sides when the head lights are on which i guess is why the circuit is not completed due to no grounding. The license plate light has always stayed on and it is feed off the drivers side wiring. I have not had a single issue with the wiring until 2 weeks ago. I feel it is some ground problem but I am going a bit crazy! Anyone have any suggestions? Thanks for the help in Advance. Shawn
The tail lights and park lights on the '60-'66 Chevy/GMC trucks are notorious for these issues. There are factory grounding straps from the firewall to the rear valve cover bolts on either side of the factory V8 trucks and one one side of the 6 cylinder trucks. There are also grounding straps from the front area of the innner fenders, to the front area of the frame rails. I have never seen any grounding straps at the rear of the truck, however, they may have existed. In any case, we I experience this issue, I install a grounding strap from the rear frame rail area, to the rear main cross sill. Additionally, I add them at the back of the tail light buckets, to the inner area of the tail light mounting cavity. I have found it easy to do, by attaching one end of the grounding strap, to the back side of the tail light bucket and the other end of the grounding strap, to the flat surface inside the cavity. 5/16" hex head, self-tapping screws work well and are easily driven with a nut driver in a drill/driver. Hopefully, this information is helpful and there may be other areas, to concentrate on, however, I have found this to be the culprit, in many cases. Good luck and keep us posted on your progress.
Thanks Lilred66 for your reply. I applied a ground strap from the taillight housing to the frame and lights magically began to work. I was supprised that the bedside fenders would not ground it. I guess 45 years of corrosion finally caught up with it. I was going mad over and was not sure what to do next. Thanks again for the help!
