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Have not been here for a while, probably because the 300D is so reliable so nothing to post. But recently my sunroof stopped working. So I went into the drivers side trunk and took a 16mm to the bolt shown in the photo to gently try and manually work it. It seems it turns pretty easily to open and close it with the socket. Then I also found that when I have it open manually, when I go to work the switch in the car the roof closes fine. But at any position with the roof open when I try to open it further with the switch it will not move. Maybe a bad portion on switch that operates the opening function, or I burned something out by trying to work the roof with the switch? Also I don't hear anything when trying to open it with the switch.
Sounds like a bad switch is a good candidate. Try jumpering the contacts to see if you get movement in the desired direction. New switches are easily available and inexpensive in ebay or salvage yards. I have given up trying to get my sr to operate correctly and have torn it apart many times.
You may want to service.it while mucking about. Mercedes Source Dot Com offers a servicing kit with gadgets to clean the cable and guide tubes as well as the proper lubricants and instructions.
Thanks for the input. On the switch contacts could I use a test light to see if I have power from the switch when I work the button? I was thinking of partially inserting the switch into its contacts and clipping one end of my test light to ground and then touching the partly visible prongs with the other end of the test light as I worked the switch to see if it lights the test light. Not sure if this would tell me anything or blow my small test light prong. Just not sure which of the prongs should go live when using the switch to open the roof.
Or if you could let me now how to jump it that would help too. Just trying to determine if my switch is bad or not or if its something with the motor itself. Thanks.
I in the trunk I unhooked the wire connector that plugs into the roof motor and hooked up my volt meter to that connection and tried the dash switch and got 11+ volts when operating the switch to open and close. So I know there is power going from the dash switch in the open and close position along the lines to the sunroof motor so to me that seems to mean the dash switch is good. Then I did several things before hooking the trunk plug wire back to the sunroof motor, such as moving around all the fuses in the engine bay as kind of a maintenance thing, and I also giggled the sunroof switch wires around some and also manually opened the roof again just like I had before. However just by chance I thought I would try the roof again with the switch and it opened and closed the roof fine. I did it a few times to be sure and it now opens and closes fine. So in conclusion I am not sure what fixed it, but I guess I determined the switch was good. Maybe it just needed to be worked some once I was able to get it moving with the switch. Not sure of the cure, time will tell if it acts up again.
Look at your photo, under your thumb is the pivot point of one side of the rocker, gently spread the lips of the switch body and the rocker can be lifted out, underneath is a copper contact that you can polish , two tiny ball bearings and two tiny coil springs, all four of these love to roll away and <vanish> for ever so work over a light colored clean fluffy towel .
Looking into the open body of the switch you'll see dirt and fuzz, plus copper posts that align and make contact with, the rounded end of the copper part you removed and polished .
Use Q-Tips to polish these too, then soapy water and a small brush to clean out the accumulated fuzz/dirt, gently re assemble and marvel as the clever design tht allows you to service it instead of replacing it .
The window switches are the same, take 'em apart , clean and polish the copper contacts and they work like new again and the windows operate faster too .
Remember : always POLISH electrical contacts ! never abrade or sand them, use METAL POLISH .
Thanks for the info. I went to take the switch out of the car to fiddle with it inside but I noticed that black wire at the top that remains hooked to the switch. I couldn't see any connector at the other end I suppose unless I removed the dash. So I gave up at the moment. However the roof is working, but maybe temporary. It seems if I am to disassemble the switch itself I would need to do it in the car with that black wire remaining connected.
04-01-2019, 01:11 PM
Balky Rocker Switches
