1980 Chevrolet Truck Wiring LIGHTS QUESTION ?

I have a 1980 Chevy truck. it is a heavy half I had it restored. I have a question about lighting. Before I started on my truck the right rear light was dim, which told me I had a grounding problem. After to get it back I hooked everything back up and I grounded the rear lights. The lights are the same light now. But, now my rear lights and front park lights don't work when the headlights are on at night. The brake and turn signals still work although. Any ideas on how to fix this? Thanks.

flawed light switch on the dash.

Nothing else....

Fuse?

Is the taillight fuse still working?

Also look at the headlights switch. that's where the park/tail/running light logic is. They should go on when the switch is pulled halfway out, and stay on when all the way out.
Did you reverse a wire at the switch?

I think you are saying that you ran a seperate ground wire for your RR taillight. That could fix the dim bulb bad ground at that place. but it seems that the ground wire you bypassed is wired in series with other lights/relays/switches, so you will have to troubleshoot that, then you will be in form. Another ground wire did not fix it troubleshoot the present one.

You should 2x check the bulb sockets for good fit and oxidation. There are some push and turn bulbs that are problematical. Also clean contact between the outside of the bulb's base and socket is needed for correct grounding.

Use a proven bulb to methodically troubleshoot and you will most likely find the problem at a wiring terminal as opposed to the wire itself.

Good luck.

i ran into the same problem with my brothers 84 truck. his lights did hte same thing too. recheck the ground you repaired. did you fix both ends or atleast reground them? that is the 1st place I could start. also attempt checking the wires coming from the headlight for shorts or just bad sheathing.