Grounding question

[75gmck25]

I did not go back through all the messages, so maybe this has been answered.

Did you check the rear harness that runs across under the truck between the taillights, and ensure the ground wire (usually white) in the harness is grounded to the truck frame? Note - I have a Tekonsha T-One connector for my trailer lights, and I’m not positive if that ground wire comes out of the original harness, or maybe was part of the adapter.

 

[Ricko1966]

I did not go back through all the messages, so maybe this has been answered.

Did you check the rear harness that runs across under the truck between the taillights, and ensure the ground wire (usually white) in the harness is grounded to the truck frame? Note - I have a Tekonsha T-One connector for my trailer lights, and I’m not positive if that ground wire comes out of the original harness, or maybe was part of the adapter.

That wire is for the trailer light ground.

 

[Ricko1966]

I've said this before, but I'll say it again. Cut a junk 3 conductor extension cord in half at the bad spot. Put alligator clips on the wires. Now plug the female into the male you have a polarized long jumper set. My male and female end are only a foot long so I can just plug them into any extension cord and have jumper wires that are whatever length my extension cord is, but the ends fit in the tool box. This way you can have battery ground or battery hot anywhere you need it. Even in your living room to bench test things run the cord through your front door. In these I think I lost ground situations you can provide a battery ground right to the component to see if that fixes the problem, before you spend a week adding a ground that wasn't the problem.

 

[75gmck25]

My error. You are right, the ground toward the center of my truck is from the T-One adapter, not the original truck wiring.

My GM wiring diagram shows a black 18 gauge wire on the driver’s side near the left taillight, and it runs to a junction that then grounds all the bulb holders for the rear lighting. If that ground wire is not properly connected, or the wire is broken, all the rear lighting would be out.

 

[Rusty Nail]

Wtf kinda ish is that? This here is on the innernet. It uses pictures and such.
New guy.
I bet u dont even got a 79 Fleetside

It don't even say what color it is...no wonder it's so slow

 

[DatKat933]

This is actually very simple. Get a 12v test light, check for power inside the socket on the little bulb contacts. Do not let your probe touch the sides of the socket. If you have power in the socket. 1 of these things is going on. 1 The bulb isn't getting good contact or the bulb is bad. Check the bulb clean the bulb and socket. Or 2 your light assembly itself does not have a ground to the bed. If you don't have power at the contacts you've been chasing the wrong side of the circuit.

I will check this next weekend when I get a chance to work on the truck again.