Electrical Troubleshooting: Windows 300SD

[Tom Wing]

I recently replaced the window relay in my 300SD, now driver's side window works, and have discovered the rear driver's side needs a regulator. Neither window works on the passengers side of the car. I was driving the car last night and noticed that the switches for the left side (the windows that work) light up but the switches for the left (don't work) are dark. What sort of issue am I looking at here?

The car is a 1984 300SD W126.120

Thanks!

[toomany MBZ]

I have the same issue on the passenger side. I can hear the rear wanting to move and decided it's the sliding jaw that needs replacement. The front door window however, doesn't make any noise, even after I replaced the switch.

[tangofox007]

Originally Posted by Tom Wing

...the switches for the left side (the windows that work) light up but the switches for the left (don't work) are dark. What sort of issue am I looking at here?

Generalized directional confusion; hopefully transient in nature.

Have you verified that the console switch for the non-working windows is actually connected? Other than that, there is no relation between the LED operation and the switch functionality.

[Tom Wing]

I'm going to check that later today, interesting. Could this mean the switches need to be replaced? Neither makes any noise at all. (right hand side)

[Diesel911]

There is threads and posts on taking apart the Switches and cleaning the contact points and crud that gets inside.

[69shovlhed]

it seems on the rear windows, if 1 switch is gummed up, both the front and rear switches will have the same malfunction. i changed the motor on rr window, during testing the motor would not turn if i pressed either switch in the down direction. cleaned out the front switch and now both switches work fine. console switch was full of gunk and filth, used a very fine scotch brite pad to clean the little contacts. i'd try that first.