PeachParts Mercedes-Benz Forum - View Single Post - Non-op sunroof 1984 300D turbodiesel

will_t · #4 02-14-2015, 01:32 AM

first, thank you all for your helpful ideas. today i carefully opened the sunroof in my 84 sedan about 6" using a 17mm deep socket on the provided "emergency" plastic hexhead on the motor. this was enough to remove the headliner (thanks to the valuable post on how to do that) and once i had that off i could see what was what. i have the factory service manual so following that I was able to completely remove the sunroof itself, as well as the drive cable. as you might recall from my earlier post, when i press the sunroof button the fuse would fry immediately. i tried a different switch but same thing. then it dawned on me that if i disconnect the power to the motor and then try the switch, if it doesn't pop the fuse, maybe it's not a wiring short and maybe something with the motor. so i did that, and with the motor disconnected operating the switch did not pop the fuse. so i removed the motor. then i decided what the heck, let's see what happens if i give the motor 12 volts directly. when i touched the jumper to the battery post it sparked briefly and then the motor ran like a brand new sewing machine! i jumped it the other way and the motor ran the other direction. it was as if it was just kind of frozen or something and that the direct power freed it up. so i ran it a few times in both directions and put it back in the car. with it back in it was a cinch to reinstall the cable (again following the manual) and once that was in i replaced the sunroof. now it works 100% in both directions. i thoroughly cleaned the tracks on the car and the slides on the sunroof, and i put a little lithium grease on both. there remains only one problem, and that is that i think the tube that is actually attached to the sunroof, the tube that passes outside the fixed cable tube in the roof of the car, must be dirty. when i operate the sunroof, especially when i close it, there is a screeching metallic scraping sound which seems to come from the tube over tube interface. so next week i will remove the sunroof again and thoroughly clean the tubes, try it by hand, and see if that quiets it. anyway, i'm no longer mystified by the sunroof, am optimistic about the eventual outcome, and thank you all again for your support.