Has anyone worked out a simple strategy for testing sunroofs that don't
function to isolate whether the problem is the switch, the motor, or something
else? Mine worked fine when I bought the car but, of course, now that the car is
in my garage, the moonroof just sits there and quietly laughs at me.
I have pulled the cover and dropped the motor/trans and tried switch then.
This only shows whether switch works though, not if motor is weak or trans bad.
What really helped mine was removing cables and cleaning the guide tubes. It is
amazing how much gunk and old grease came out. When clean I used white lithium
to re-grease cables and installed.
If motor is working then trans is next. You can open this carefully (it is pot metal and crimped) and clean/re-grease also.
If motor is good but switch not working then disassemble switch and clean contacts (probably should do this one first)
are both directions of the switch inoperative? on mine sometimes the back
part (sunroof opening doesn't engage) but when I depress the front part I hear
the motor briefly. if so then the switch or the back contact is not good.
also trying isolating pressure on different parts of the sunroof open part. with mine I have to isolate pressure on the left side about 2/3 rds back. I can usually get it open that way. I spayed some electrical contact cleaner on it first.
seems that's the first place to look, especially it worked when you tested it. same kind of thing happened to me.
Another problem area is the to hinges that the front guide bar attaches to.
Only problem is you have to get the roof partially open first to get the roof
liner out. You may need to get out the old hand crank! These hinges allow the
front of the roof to pivot so the back will drop when opening. Did my rebuild &
did not address these hinges & the roof tried but would not budge! Had to spray
them & work them till good and loose, then all was nice!! Naturally, this is
after you have all the electrical stuff in working order.
This is what the bowden cable and guides look like.
1992 928GTS midnight blue