Driver side passenger power window problem
 

89 190E 2.6...newbie owner

Driver's side passenger power window will not actuate. Neither the console switch or the passenger switch will actuate the window.

Is it possible both switches could be bad? Could the relay be bad? Or the motor? Where would I find the fuse and relay, for just this window?

How do I check to see if the relay is bad? What is the procedure to check for bad switches?

Any advice at all here and the order in which to check the problem would be EXTREMELY helpful as Im running blind awaiting a repair CD. Its getting hot and the A/C is dead and I need to roll this window down!

Thanks.

Just to share my most recent window mechanism incident...last Xmas...

...driver's side window on my W124 stopped functioning. It only has the console switch so I don't have the issue of which switch is bad. Figured it was mechanical since I could hear the odd rhythmic clunking noises prior to its demise.

Pulled the panel and the entire mechanism out of the car. Took it to my indie, hoping he had a spare motor he could swap out from one of his donor cars.

We tried a known good motor, and still no budge. Took my motor to a known good mechanism and it worked! Determined that the gearbox mechanism had seized.

No other gearboxes available, so I had to order an new OEM part. :mad:

Okay, back to your case:

Do this one at night, it's easier.

with the door open (so the courtesy light is on), hit either the panel switch or the console switch. If the courtesy light dims briefly when you depress either switch, then the fuse, switches, and any ?relays? (etc. are fine). That would point to the mechanism, the motor, or the gearbox.

You would have to take the assembly out and diagnose at this point, in a similar fashion as my indie did...

Here's the thing....

The rear courtesy light isnt working....now, I havent checked the bulb or the fuse, but will do that first.

The courtesy light and that window would be on the same circuit? seems strange but will do.

Thanks.

What I was trying to demonstrate is that without using any tools (like a multimeter), you can get a pretty good idea what to rule out by trying this simple test.

The courtesy light isn't necessarily on the same circuit, but the current draw would affect the rest of the circuits...you can't measure that w/o a tester, but the dimming light would be a sure sign.

When you press the window switch, the motor draws current. When the window reaches it's stop limits (up or down) and you are still pressing the switch, the motor can no longer turn, but in it's attempt to still provide torque, it draws even more current...enough to briefly starve the other circuits in the car (hence, the light dimming effect).

If your motor is working but the mechanism is inoperable, the motor would try to operate, but the jammed mechanism would prevent normal operation, thus increasing the current load (dimming light). If the switches were bad, no current would be applied, and the light would not dim...make sense?

Gotcha, my good man...
 

Makes perfect sense.

For ****s and giggles I will look at the courtesy bulb and proceed from thereas per your instructions.

Electrical troubleshooting has never been my specialty which is why I own a 55 year old HD Panhead, keeping things to a bare minimum.

In any case, I m thinking the motor is toast, but hoping for the best.

Heres a good "how to" on troubleshooting your windows.
www.msdra.com/mercedes_power_windows.htm