Both rear windows no longer go up/down. - PeachParts Mercedes-Benz Forum

ps2cho · #1 10-10-2008, 08:29 PM

None of the buttons make either of them go up and down. When I got the car, just the rear right side didn't work, but last week the left side has given up too.

Is this the window regulator that has failed?

Anything else it could be?

Got some time this weekend (first in a long time) so I'm gonna be as productive as I can.

Much appreciated.

93_300E2.8 · #2 10-10-2008, 09:26 PM

The regulater might be bad, the switch might be, or there could be a break in the wire in the door jam's. that would be my guess.

J.HIDALGO · #3 10-10-2008, 10:14 PM

That should be your clues. Try this: Shut the door while pressing the up or down button. This may "unfreeze" the motor, long shot but, nothing to loose.

Bob Weir · #4 10-11-2008, 01:35 AM

Hopefully you'll find the electrical commonality in the attached schematic. Unfortunately the wire color codes are fuzzy on my original. This schematic is from [2 cd] 124 manual.

Because both rears don't work, I'd rule out motors & regulators.

TAG · #5 10-11-2008, 07:14 AM

On my 300E it was the wires in the door pillar. It's probably the easiest thing to check. Pop the rubber boot. Mine had pushed through a small rip in the wrapping. I did pull the door panel and rerouted the wires a little bit so they didn't flex in the same spot.

pmckechnie · #6 10-11-2008, 07:52 AM

Don't rule out anything yet. Try this. Open a door so the interior lights come on. Ign on, engine off. Look at the interior lights very carefully while hitting the window switch for one of the good windows. You should see the light flicker ever so slightly. Now try one of the bad windows. If it does the same, then it is a regulator or motor most likely. If it doesn't flicker the same as a good window then it is an electrical (switch, wire, etc) problem most likely. When looking for an electrical problem on the rear windows remember that the front OR rear switch could be the problem.

ps2cho · #7 10-11-2008, 10:17 AM

Ok thanks guys I'll test the door close while holding the button and see if the lights dim slightly when pressing the buttons too.

cdplayer · #8 10-11-2008, 11:40 AM

I realize you had some trouble with one of the rear windows recently. And now both. I am trying to help another member with problems in the driver's switch. And it occurred to me the child lockout switch died. Have you ruled this out? How does this switch lock both rear windows at the same time. If it is dying, could it lock one then the other down the road?

ps2cho · #9 10-11-2008, 07:55 PM

Quote:

Originally Posted by cdplayer

I realize you had some trouble with one of the rear windows recently. And now both. I am trying to help another member with problems in the driver's switch. And it occurred to me the child lockout switch died. Have you ruled this out? How does this switch lock both rear windows at the same time. If it is dying, could it lock one then the other down the road?

Interesting...How could I rule that out?

Quote:

Originally Posted by J.HIDALGO

That should be your clues. Try this: Shut the door while pressing the up or down button. This may "unfreeze" the motor, long shot but, nothing to loose.

Tried it for the heck of it, but no success.

-----

I tested the buttons and the interior lights dim so it must be getting power. How can I tell if its a regulator or motor problem?

J.HIDALGO · #10 10-12-2008, 09:40 AM

You can test power with a voltmeter. You can rule everything else once the door skin is removed.

cdplayer · #11 10-12-2008, 12:01 PM

Quote:

Originally Posted by cdplayer

I realize you had some trouble with one of the rear windows recently. And now both. I am trying to help another member with problems in the driver's switch. And it occurred to me the child lockout switch died. Have you ruled this out? How does this switch lock both rear windows at the same time. If it is dying, could it lock one then the other down the road?

Providing the switch plugs on the W124 are similar to W126( I am implying that same side front and back switches on said vehicle are using same style plugs), lift the console that holds the switches. Unplug one of the rear switches. Unplug the front switch on the same side. Right now you know the front switch 'works' because only the back windows are inop.
Plug the front switch into the rear plug(same side of vehicle).
If the lockout switch is causing your problem, the 'front' switch plugged into the rear plug will still not make the window move.

Another member was having a similar issue with his W123. Lockout switch was the problem as well. Just FYI

JEdwards · #12 10-13-2008, 08:35 AM

I'll just throw in my 2cents. This happened w/ my 300E. A friend and I took the door apart and lubricated the window regulator (they were somewhat frozen up by the metal wire). This worked well for one. On the other, the motor failed with the window in the down position. Long story short, I ended up replacing the window regulator and motor (you have to replace both at the same time), but had to drive around w/ the window held up by a piece of wood.

My advice is to leave the back windows alone. The window regulators are a terrible design and them not working doesn't affect the driver at all.