need advice on 300E rear power windows not working

[cangold]

hi...My rear power windows don't work..not switches or relays.Need advice on what the cause may be.. thanks for this forumI have saved lots of $$$$ from you guys

[JerryWagner]

There are seperate fuses for each side, I would check those first, if you have faulty or un hooked switches at the rear doors the driver's window switches will not work, if it was my car I would first check the fuses, then check and make sure the switches are hooked up and working properly, I would then remove the door panels and take a hot wire from the positive side of the battery and apply power to the regulator motor to see if the motors work and then use a 12v lead tester to see if I am getting power to the motor, let us know what you discover

[simmo300e]

if it's not switches, relays or fuses, it's... the motors. This, apparently, is a Known Fault.

Replaced all four on my 300e since buying it 18 months ago. Back rear only went down halfway when I bought it, within a few months the others got noisy and packed up entirely. The driver's side did fool with me a bit by making its own mind up whether it would work or not, and I replaced the front passenger motor anyway because it was making too much noise, despite lubrication.

Bad news is that the rear motors come attached to the regulator, which makes them a bit more expensive. Fronts you can just swap out the motor. I paid about $150 each for the rears and $100 for the fronts.

While you're messing with the doors, it is probably worth your while to take a look at the door stops. They tend to get noisy and crotchety with age. If they haven't been lubed over the years, they will eventually seize, as mine did, leaving you with a door jammed open down the supermarket.

BTW, if this door jamming ever happens to anyone, give the door one hard shove to see if it will close. If it does, climb in the other side and drive home to fix it. My experience tells me that you only get one shot at this. When I opened the door again to see if it was back to normal, it jammed up solid, to the point where the door stop started to bend instead of freeing itself. Had to unbolt the unit.

I've already replaced two doors stops, and will be doing the other two before too long. They are sealed units and 17 years is a long time on one shot of factory lube.

I've given up thinking of this as maintenance, makes me feel better talking about it as a restoration project.

good luck

[mbdoc]

When you press the rear window switches(with door open) does the dome lamp change intensity?? IF not then you probably have a ground wire problem!

ON the rear doors with the lights on can you see the switches light up? IF not then you DO have a ground wire problem.

[Tigger300E]

Originally Posted by M.B.DOC

When you press the rear window switches(with door open) does the dome lamp change intensity?? IF not then you probably have a ground wire problem!

ON the rear doors with the lights on can you see the switches light up? IF not then you DO have a ground wire problem.

M.B.DOC, could you post some more specific info about this issue? My rear driver's side window won't work and the switch doesn't light up. How do I solve the ground wire problem?
TIA

[mbdoc]

On USA cars the child safety switch provides ground to the rear seat window switches, both for operation & for the led in the switch!

[Tigger300E]

Originally Posted by M.B.DOC

On USA cars the child safety switch provides ground to the rear seat window switches, both for operation & for the led in the switch!

mine is a USA version MB - so the problem is in the child safety switch? when I move it the rear right switch lights up, but the left one doesn't. should I pull out the child safety switch and check it?

[cangold]

Originally Posted by M.B.DOC

When you press the rear window switches(with door open) does the dome lamp change intensity?? IF not then you probably have a ground wire problem!

ON the rear doors with the lights on can you see the switches light up? IF not then you DO have a ground wire problem.

hi The rear window switches do light up with lights on .... also noticed when I flip the child safety switch the led in rear switches do go on and off. Still the window don't work..

[haasman]

Also, turn the fuses in their respective sockets. This type of fuse can often appear fine, no breaks, but have corrosion at either contact end.

I periodically rotate all the fuses to ensure good contact. Some people remove the aluminum fuses with the copper link type.

Haasman