Head light/ clearance marker problems!!

I would say one of the contacts in the plug is not making good contact. Or is dirty. They make tools to get the wires out of the plug without destroying them. If you are careful you can do it without the tools, sometimes a thin piece of wire, really small screwdriver. At the age of your truck there is usually a film on those contacts and it can create problems. There is contact cleaner, but I like to try and get some scotch brite or something in there to shine up the surface. I would also try and tighten up the contacts if that cab light contact is a little loose that could be your problem. Look at the plug and see if it has been hot. As in melted plastic.

 

Agree......A little dielectric grease on the plug may help too after cleaning the connections.

 

May have to dig back in harness and try to get some slack,then zip tie as close to switch as possible. Also look down in plug and see where contacts are,then bend pins slightly to tighten up.

 

take a look at your relay it can be causing this issue. i had the same problem you described a few days back turned out to be a corroded relay