power window not working W126 - PeachParts Mercedes-Benz Forum

mak · #1 04-20-2009, 09:03 AM

my passenger side power window has stopped responding. i have replaced the power switch but no operation .
Advise appriciated
Thanks
mak
300se 89 W126

MB Neo · #2 04-20-2009, 09:11 AM

Are you getting any power to the motor? If not check the fuses. If you are it seems it would be the motor failed and needs to be replaced.

tinypanzer · #3 04-20-2009, 08:39 PM

Yes, first check the fuses. Although, I think if it were a fuse you'd have two windows that don't work....

Do this - try the window switch with the engine off (but ignition on) and the door open. Do you see the dome light dim when you activate the switch in either direction?

If so, then you can rule out fuses. Also, you can say that the motor is at least drawing current and trying to work. If that is the case, the problem could be a either mechanical (a jam) or the motor might be burned out.

If you are sure the fuse is good, and the thing won't make the dome light dim (try this at night) when you try it, then the motor is either completely burned out or there is a wiring fault (open circuit in either case).

mak · #4 04-21-2009, 01:38 AM

i have removed the door card and applied current directly to the motor . the motor runs up and down when the wires are switched .

As i rechecked, the rear left window is also not operating yet the fuses looks ok.
mak
300se 126

pmckechnie · #5 04-21-2009, 07:45 AM

On these old cars, the only way to check a fuse is with a test light (lights on both ends of the fuse) or replace it. This is true of any fuse on any car. Every one should have a test light and learn how to use it. In my auto electric business we use test lights for every thing except the computer systems. Very seldom is any thing else needed.

Paul

tinypanzer · #6 04-21-2009, 06:34 PM

Yeah, replace the fuse. If it is original, it can look just fine and be bad.

Your symptoms fit this exactly. For some reason, the front driver's window is on the same fuse as the rear passenger side window. The opposite is also true. I guess there's some German logic behind why they did that, such as escaping from a car lying on its side...... You always have at least one working window per side with a blown fuse.

Anyway, either the fuse or the circuit has an open condition. Buy a whole bunch of new fuses. Use the newer brass type rather than the originals which tended to suffer from oxidized ends. Problems start going away as if by magic when you replace them all at once I have found on more than one occasion.

Good luck....

mak · #7 04-21-2009, 10:06 PM

Thanks for the advise .matter of fact replaced all the fuses with fresh brass ones from a fuse kit. next check point please.

regards
mak

tinypanzer · #8 04-22-2009, 07:38 PM

When you replaced the window switch, did you use the switch that is for that window, or did you borrow one from another window?

Those switches for the most part are NOT interchangeable. The rears and fronts are totally different, even the ones in the center console.

Test with a meter to make sure you are getting +12 to the switch. If not, there is a wiring issue upstream of there.

I am starting to lean towards wiring issue since you have two windows out on the same circuit.

The only way to troubleshoot that is to get a wiring diagram and test point by point. Start at the fusebox, and work your way back to the switch. Once you have verified you are getting voltage to the switch, work towards the window motor.

Make sure the fuse didn't blow after you replaced it. I once had a bad rear window switch that would cause the fuse to blow every time I tried to move that window from the front console switch. When it went, so did my front window...... I chased it around forever, thinking I had a wiring issue, but I just had a bad rear window switch and it was on the same circuit as my front window.

mak · #9 04-22-2009, 11:41 PM

i first moved the rear window switch to the front until the correct switch arrived for the passenger side , i understand these are left and right handed for the correct sides. is there a on line wiring diagram for window wiring.
thanks
mak