Hello, I am new owner of a beautiful 1984 300d. I have been through many of her systems and have been lucky enough to diagnose and repair many minor leaks, etc (thanks to many of the posts here), but I have one last annoying issue.None of my windows work consitently. They are all dead and have been so for months, but, sometimes they work for the first few minutes the car is running. I have replaced the fuses a few times, and while they never seem to blow, the windows only work for the first hour or so after I replace them. Any thoughts on what to try next?

 

I had much the same problem in a post 2 weeks ago....in benzworld.com
look in 126 sedan forum....
for me the most effective thing was removing the panels to access and clean the wire connections from the window motor to the connection screws about 30" away. It was a ground fault. Most electrical weirdo problems are.

 

I can't seem to fnd that forum on benzworld.com, but thank you for the advice on tracking down the ground. As it is all 4 windows at once, do you know where the wires converge from all the motors?

 

If they work after replacing a fuse, then clean the contacts that hold the fuse. The grounds terminate at the switches. Remove each switch and spray them with TV tuner cleaner. Or, if your able, remove the chrome bezel surrounding the switch and clean the internal brass pivots inside. Rather a slow and tedious job but usually thats all they need to regain function. Are you replacing the fuses with brass element type fuses? They tend to not corrode as fast.

 

Thank you carnut. I am, however, still frustrated. I have cleaned and changed the fuses mutiple times, but I can no longer see a correlation between them and the windows working. They windows are at best, intermittant. Can you please explain the chrome bezel in more detail? I have taken offthe housing for the window switches, and they look to be mounted separatly and plug into separate sets of wiring. I am fairly sure it a ground problem, but I am still not sure where to look. Any suggestions would be much appriciated. Can one bad switchstop all the windows from working? Where is a good place to get copper fuses of this kind? My local auto parts store was clueless. Thanks in advance.

 

Either copper or brass, just not the grey metal element in the original fuse. Any auto parts store or independent foreign auto repair shop should have them. With the switch in your hand pry a small screwdriver around the perimeter of the chrome bezel. It will slowly lift from the switch. Now the fun begins. Inside are 2 brass rockers with small springs. They will pop off!! Clean the rockers with sand paper and reassemble. Easier said than done unless you're very mechanically inclined. You also can swap switches left to right to see if the problem appears with another window, confirming a faulty switch prior to disassembly.

 

It is all of the wondows or none, so I amhesitent to dig into individual switches.