<snip>
What else can I check?
<snip>

It's likely the backup light switch.

Early in the fall, my backup lights, which had been a bit flakey for a
while, quit working all together.  I disconnected the wires from the switch,
put the van in reverse and turned on the key, and put a meter on the wires.
Had voltage.  Switch not making.

I had to order a new switch, so, having time on my hands, I removed the old
switch and, using Ronsonol lighter fluid, I cleaned the old switch as best I
could by squirting fluid alongside the plunger and working it in and out ...
numerous times.  A paper towel was used to sop up the black stuff that was
being washed out.  When the fluid was finally coming out clean, I lubed the
plunger and checked it with a meter.  It was working.

I reinstalled the old switch and it worked flawlessly.  When the new switch
arrived, I put it in the spares locker where it remains today.

Mike
Houlton, Maine
'84 GL 7 pass automatic
'85 GL Westy 4 speed