1991 Tioga rear running lights?

You might remove the bulbs and measure from a ground source (chassis) to each one of the ground studs to try and determine if one is causing the problem. My studs were loose as well but since they are mounted in fiberglass there must be a wired connection or ground plane on the other end of the stud. They tightened up once the nut was tighted down so you probably want to do your measurements with the nut tightened down. I know my lamp assemblies were in a pretty sorry state so I was glad that installing the new ones eliminated all my problems. If they had not I would be in the same situation you find yourself in. I would concentrate on trying to find the source of the faulty ground (or power connection) if at all possible. Maybe that will give you a clue on how to proceed.

Sloop Smitten wrote:
If your Tioga is like my Jamboree the grounds in the rear running light are via one of the two threaded studs that hold each light in place. I would remove each lamp and clean the stud amd mating surface in the lamp and see if it improves. It might be a good time to replace them all if they are the original lights. They are relatively inexpensive. The grounds are wired in series so a difference in voltage often times is linked to a bad gound connection somewhere. The positive connections are in parralel however.

You are correct the ground does go to the mount stud. I have removed and cleaned them all. Some of them do not feel like the post or stud coming out of the rv shell is very stable. Like its not secure. If I thought I could fish the wires I would replace them all with LED's.

Usually it is not the wires, but not impossible. Go over all the connections again. Use a meter with a continuity tester. Jiggle things around and see what's up with the continuity.

Hopefully its just a simple bad ground somewhere. If they are flickering together, that's what I'd check first.

If your Tioga is like my Jamboree the grounds in the rear running light are via one of the two threaded studs that hold each light in place. I would remove each lamp and clean the stud amd mating surface in the lamp and see if it improves. It might be a good time to replace them all if they are the original lights. They are relatively inexpensive. The grounds are wired in series so a difference in voltage often times is linked to a bad gound connection somewhere. The positive connections are in parralel however.