chasing a ground problem

[Gator70]

So, I have a ground issue with my tailights. When i took the lens housings out the mounting screws had some sort of rubber?? behind them. Is that rubber, or something else. The screws hold the assy against the box and help create the ground. If it is rubber what creates the ground for the assy??

Any advise would be good, my beer budget is getting shot trying to chase this problem down.

[BADPURPLE70CHEVY]

When i put my bed back together i had a similar problem. Turned out to be a ground wire in behind the taillight assembly. GOOD LUCK

[cdowns]

i always run a ground cable from one of the crossills of the box to either a crossmember or frame rail to ground the box to the frame /it solves alot of problems

[Classic Heartbeat]

That stuff behind the screw is sealer. I use 3M Strip Calk adheisive in its place. It keeps water from getting inside the housing from the back side. The housing will ground to your bed once the screws are tightened. How does your sockets look? Or the taillight harness? WES

[Gator70]

Thanks for the tips. I am trying to avoid pulling the whole harness out, but the sockets/connections are in suprisingly good shape. I can only feel up to the marker light splice and it feels pretty good. The nut clips for the mount screws are pretty rusty, I am going to try and get those off and clean them up.

I dont recall seeing a ground wire on the wiring diagram, or part of the harness. Where is that wire. The marker lights have the single lead and then grounded to the box. But I didnt see anything for tailights or back-up lights.

[Classic Heartbeat]

The taillight housing and backup lamp housing do not have seperate wires to ground them. They are grounded through their housings. WES

[Gator70]

Thats what I thought Wes. Thanks. Maybe another wire like cdowns said would help things out. 40yr old connections can be a little fickle.