Originally Posted by Mike M
I have a 1989 Excella with a license plate lamp that works only intermittantly....
Welcome to the Forums.
I totally agree with Jim's comments on the grounding problems.
I just the other day buttoned up the center rear panel under the window (the "front" panel to the license plate bracket), so I can attest to the wiring.
Pulling the center interior panel is no biggie - about 50 or 60 rivets is all.
On the wiring - both the positive AND the negative (ground) wires had "quick connects" on them...in addition, the ground was routed to the curb side and connected with several other wires (grounds for the curb side running lights) before being connected to the body for grounding.
On the new license plate bracket I installed there was NOT a wire included for grounding - the ground is implemented through the screws which hold the bracket to the body.
You might try replacing the bracket screws (even on my old one - '78 vintage Sovereign
- the bracket attach was via sheet metal screws - not stove-bolts and nuts), sometimes the screws become a bit loose and a thin layer of rust developes between the screws and the aluminum.
Be sure to use some sort of vapor barrier on the new screws to prevent water from entering the rear of the trailer at this point - the rear 6" or so of the floor was the only area I found moisture damage when redoing the '78.