W108 Electric Rear Window

[K-Jet]

Good afternoon!

When I got my 1971 280SE, one of the niggles was that the passenger rear window would not roll down. I traced the problem to the front window switch and replaced it. Now the window goes down. With the down switch on the door and the up switch on the front switch. I have mapped the connector and matched the wires (and swapped a few!) and done all I can think of, but I can't seem to make the switches go in the same direction.

Anybody solved this problem before, or have an idea how to?

Thanks,

K-Jet

[ja17]

Probably dirty contacts in the switch. They can be opened up and cleaned. (A bit tricky to keep the tiny spring and ball in place during re-assembly.)

[K-Jet]

Dirty contacts would cause the front switch to work backwards from the back switch? Both switches work reliably in both directions, they just work in opposite directions.

Currently the front switch causes the window to go up when I press up and down when I press down. But the switch in the rear door makes the window go down when I push up, and up when I push down.

Or I can swap the motor wires and the door switch is correct and the front switch is backward.

I metered the switches and checked the voltages and several times came to the firm conclusion that if I only swap this wire for that wire in the connector the switches would both work correctly, but all I got out of that was blown fuses.

[rwmastel]

Before you replaced the front switch, did the rear switch operate the rear window at all?  Did it work properly?

[K-Jet]

It did not.

[BobH]

Hello, these motors are reverse polarity, so the switches reverse the +ve and ground supplies to the motors.  The front master switch and rear switches should work independently of each other

Have you got a wiring schematic, or are you connecting and changing the wiring around blind?  i think you really need to follow the schematic wire for wire, and then surely both switches should work correctly

[rwmastel]

If no schematic is available, then just replicate what is working for the other rear window.

[BobH]

I found this if you don't have one, hopefully the electric windows circuit is the same for your car

https://www.benzworld.org/attachments/15-17-pdf.419480/

Just a thought, if the switches are plain, unmarked, can they not just be turned around, never seen one, so just a thought

Nice little sketch to show how the switch reverses the polarity to the motor

https://www.12voltplanet.co.uk/downloads/12V%20Electric%20Window%20&%20Aerial%20Switch%20wiring%20diagram.pdf

[K-Jet]

Bob,

Thank you. The wiring diagram is more complete than the one I have, which only goes to 63.

What would happen if I switched pins 1 and 5 is the same thing that happened when I switched the wires on the motor side- both front and rear switches would work the opposite of what they do now (and still opposite one another).

Maybe the hope is in trading pins 7 and 8 on the front switch (marked 62a)?

[BobH]

I would trace the wiring and make sure it's correct as per the schematic

5 on the rear switch, black/pink to 7 on the front switch
3 on the rear switch, green/black to 8 on the front switch

[lpeterssen]

Dear Dru

Do you have a digital copy of the oily wiring diagram you show on the picture?

I would like to have one if possible.

I have not replied to your question coming in, but I think that Bob help you right with the correct schematic for later version power windows.

Next time write me per email, I am willing to help if I have the information.

That schematic Bob gave you I have it too.

Best regards
Lp

Bob,

Thank you. The wiring diagram is more complete than the one I have, which only goes to 63.

What would happen if I switched pins 1 and 5 is the same thing that happened when I switched the wires on the motor side- both front and rear switches would work the opposite of what they do now (and still opposite one another).

Maybe the hope is in trading pins 7 and 8 on the front switch (marked 62a)?

[ja17]

How about just rotating the switch on the door 180 degrees?