300sl window and top issues - PeachParts Mercedes-Benz Forum

944s2c · #1 07-01-2006, 11:47 AM

Hello all,I have a 1991 300sl with the following problems:when using the switch to lower soft top,the REAR of the top unlatches,raises,top cover opens,the windshield latches(left and right)do not open , causing the top to freeze in this position.Reversing the process,every thing closes back up.Noticed that the right window does not lower when lowering the top or actuating the window switch.I can hear the relay switching behind the seat when the window switch is activated.I checked for voltage @ the window motor and found no voltage.I believe the window problem and the top problem are related.I pulled codes from the diag connector and got codes 17 & 18.Can I assume the window switch is good if I can hear the relay behind the seat clicking???? Can any one advise me on the codes?Thanks DAN

mbdoc · #2 07-05-2006, 09:22 AM

Is there a blown fuse for the window in the trunk???

IF not then the window motor may be the problem...

The window MUST go all the way down on the car for the top to completely function...

944s2c · #3 07-07-2006, 10:23 PM

M.B. Doc,thanks for your reply,I checked fuse block up front but only found fuse for top controller,which was OK,couldn't find fuse for the windows.So I checked EVERYTHING including window motor(applied 12vdc to motor),the wires from the controller , found no shorts,good continuity,found no output from the controller......then I remembered the fuses in the trunk,sure enough the right window winder fuse was fried.I replaced it and every thing has been fine for 5 days now. I think these ceramic fuses get TIRED after time and should be replaced every 10 years.Have you had any experiance with these fuses just wearing out over time? Thanks,Dan

bhatt · #4 10-03-2006, 07:47 PM

As a (hopefully helpful) note to anyone who digs up this thread in the future and has a similar problem...

Had the same issue but with the left window in my 90 300SL. Looked at the fuses in the trunk and they looked fine. Wasn't sure which one was for the left window motor anyway (there appears to be NO diagram anywhere of which fuse in the trunk does what).

Pulled off the door panel and tested the motor for 12V.. nothing.
Ran 12V to the motor and it sent the window up and down just fine.
Never suspected the switch, because (like the original poster) I could hear a click from behind the drivers seat when hitting the switch.. how could the switch be bad?

Then I found this post and looked VERY closely at the fuses in the trunk.

The very top one was all crumbly and it came apart into bits when I removed it. Put in a new one and everything worked PERFECTLY!

Then I spent 45 mins putting the stupid door back together which I didn't need to remove in the first place

So we now know two things...
1. ALWAYS check the fuses in the trunk first. Replace them all if you think anything is weird. Funny thing is, I've always replaced every fuse when buying a used MB. Never did it on this car for some reason....
2. The topmost fuse is for the left door window. Not sure what the others are but I would assume #1 is left window and #2 is right window.

Hopefully this is helpful if anyone has the same issue....

Neal