as I have posted here concerning this issue let me share my findings....problem: 2 weeks ago on a 1990 300TE, for no reason seemingly the power windows, seats, sunroof and windshield wipers all failed simultaineously. I spent 2 weeks going over the relays, controllers and so forth with no success. It became apparent that the module under the rear seat was causing all of this and the only reason could be that it wasn't getting powered up somehow. But where does the power come from to this module? I went through every fuse in the fuse box with a circuit tester, took every fuse out 1 by 1 and examined it and checked the circuit for leaks..nothing...then after replacing a couple of OK looking fuses and feeling down the whole damn shooting match came back on-line...it all works.....I still don't know what fuse or what I did made it work but it does...I think a fuse got out of line or something and wasn't making a total connection, either that or there's a short under the fuse box that will come back later...either way....it's free for right now....

 

Cliff.

Issues of this type are often down to the stiffness of the wiring / cable immediately below the fuse box.
The cables exert a loading on the prongs of the fuse holders and in so doing CAN reduce the contact pressure between the fuse and holder (usually this occurs with cylinder type fuses although I guess your car has continental type flat pin type fuses however I guess you get the idea.)

Low contact pressure means that an oxide layer can build up between the electrical contacts leading to intermittent operation.
Low pressure can also allow local heat to build up due to high resistance in the contacts.

Finally water / dampness can cause electrolytic corrosion to take place since the water acts as an electrolyte and causes the contacts to "fizz" away or at least reduce the conductivity of the contact surfaces.

Need to determine which fuse supplies the controller to which you refer and then examine the fuse box area VERY carefully pulling and pushing the wires (carefully) until you can reproduce the failure.

Good luck.

Stuart

 

Cliff,
In the game of 'hunt & peck', I always find it prudent to stop and test at every phase of the repair. If you do say, a dozen 'fixes' on a electrical system and it works, you never really know for sure what the 'fix' was. That in itself is a form of madness. I always like to know what the actual fix was, or at least down to two possible repairs. Either way, my fingers are crossed for you and the MB voodoo relaxes a bit.

I got new tires this weekend and the older counter dude argued with me that 'they' don't make V rated tires in my size. Since he was selling me Toyo's, I said look again. Sure enough, in his computer where V rated Toyo's. Not backing off an inch, he went on to tell me in his 28 something yrs there, he never sold any. I felt like saying that's because if you live in this town, you live in a 'box', but it's better to pick my battles I'm finding. Even the tire monkeys could see my brakes need renewed, the front struts are shot and a few suspension pieces need replaced. I was amused as they pointed all this out to me as if I were uninitiated mechanically (they had also never seen an independent, self-leveling rear suspension before). Pushing hard for a service appointment, I said no, not here, not this car. A lot of the time they can't even spin balance tires properly on their tire machine. If I was trying to save money and entrust them, then I would deserve whatever happened with a tire box store.

Kevin

 

Amen. I have learned the hard way too many times. You get what you pay for. A trustworthy and knowledgeable indie mechanic is perhaps the best working relationship you can have. Beware the average tire store guy... they DO live in a box and they don't understand what goes on in the automotive world outside of what they see come thru the shop.

 

I agree entirely...all that I know is that it worked and has fora while now. I think a fuse was the problem, not seated properly. I just had a stereo installed so...anyway..I thought way through the problem and it ended to be the very first thing I should have done....check the fuses....

 

If you stop and think about it logically; if they had never seen an independent, self-leveling rear suspension, why would they think I'd let them touch anything mechanical on my car??

Oh well, as I said, I pick my battles these days. Besides, I LOVE working on this car and I have genuine respect for how the Germans so thoroughly engineered it. I take a 5,200 mile trip with it as is and it performs flawlessly, even at high speed. If it were anything but a MB it would be looking and behaving like the 'family truckster' (National Lampoon's Vacation), Chevy Chase drove...after it went airborne.

Kevin

 

I just did the new stereo bit myself. Guy wanted $400 to do it and maybe more. Definitely would have been "more" for going into those doors and not breaking anything. Besides, I got to see inside a virgin door (passenger side front) and a bastardized door (drivers side front) that someone had been in previously. The difference was remarkable. I can't say it was 'fun' putting that system in....especially when I had to fabricate a crossover plate out of Plexiglas, so I could mount the crossovers next to the rear window washer fluid bottle. I did a little bit every weekend until it was done with one of the boys I mentor. Now we're looking for excuses to travel...lol. Funny thing is that he had to explain to me how that Kenwood receiver worked with all its displays and BS (are they born with this knowledge??). I guess these days you have to be enchanted by the receiver graphics.

What system did you put in Cliff; amp/receiver, speakers, size, brand etc? There's so much out there, I'm always curious about what owners pick. I just couldn't bring myself to do a sub in that wagon.[:'(]

Kevin