1998 C230 rear window not working

[ptcruiser]

This is a first post for me, as I was told that this site is strictly a 202 site, and possibly quicker answers.
The question is, my RR window won't go up or down.
I removed the center console window control panel, and disconnected it. I popped off the rear window switch, and disconnected it as well.
There are 3 wires connected to the switch plug in. One is light blue, one is brown with a blue stripe, and the other is brown with a green stripe.
The wires are VERY thin going into the door panel, and I had planned to just do a 12 Volt jump to see if it's the motor or the main switch,
but I am concerned that 12 Volts to that size of wire will fry it in a second. It was mentioned by an old Mercedes mechanic, that the window may
operate by a signal pulse from the computer, but he stopped working in 1993, so it was a guess.
Any suggestions if it can be jumped direct, or is there a specific fuse on a window by window bases, or ????????
I appreciate any comments and experienced suggestions.
Regards

[taz069]

Glad to see you made it. I'll say don't jump it from the center console yes the wires are super small. The panel over the back door has only 3 screws well on mine(96 c280) by the door latch, one under the arm rest, one behind the door handle cover several panel clips around the outside edges and it should pop upward. I have not pulled the window motor in the rear door but i did on the drivers side. And used some jumpers hooked straight to the battery. Wasn't really consernd about +/-. , it's runs both way's one way for up and one for down. Mine has only 2 large wires going to the motor.

[strictlyspeakin]

Brown with Blue does look like a signal wire.
I'd get into the door like taz suggests. Make sure voltage is arriving before you try jumpering

[ptcruiser]

Not sure what you mean "a signal wire"....All wires are the same size (very small) and the brown with blue I believe is the middle wire of the 3

[strictlyspeakin]

I think you are talking about the wires at the switch in the rear door. The wiring diagram has a note on that wire "Sig." I take that to mean that it is for the one touch auto down type of feature.
I think there are 7 wires that run into the motor control in the rear window. 12V, ground, 2 from the CAN bus (switch in the front) and 3 from the rear switch. It's hard to know where you plan on hooking up 12V to.
Using a good ohm/volt meter, find out if you have power back there. If you do, you can measure if the switches are working. I doubt both switches failed at the same time so I doubt those are the problem. I presume that neither switch makes the window move.
You are left with is there power at the control box? yes - either the control box has failed not telling the motor to move, the motor itself has failed, or the window lift linkage is jammed.

As far a voltage is concerned, 12V will not fry the wire necessary. How many Amps you try to draw across that wire will determine if the wire will fry or not. A 12 volt 1 amp draw is significantly different than a 12 volt 30 amp draw. The latter being more powerful and would require a smaller gauge (bigger around) wire. Hope that makes sense.

[taz069]

My 2cents. Sorry strick. The motor wires are 12-10 gauge on my window motors. The control wires in the console are in the 16-22 gauge range. And they simply control the solinods in the relay box either thru pulse or low voltage. Not for sure. Let me run and pull the switch in my back door be right back!!

[taz069]

Miss understood. Please do not hook power to the small wires!! Even a 98 has a control box for the windows some where!! Pulled the back door switch 4 wires grey/ blue, blue/white, brown/tan, and green/red. And they are all to small to carry said amperage to window motor. Please find the control box.

[ptcruiser]

Took off the door panel to go direct to the motor, and the motor was disconnected, and the connector was tucked neatly in the interior panel. I reconnected it, and it works from the center console up and down, and the rear door window switch will make it go down, but not up. Looks like I need to replace the window switch, but I will test it first. Why it was disconnected is a mystery to me ??????
Thanks for the help and suggestions.

[taz069]

So the motor was disconnected! Things that make you go hum. All good you found part of the problem! Net me know what you find out!! My driver window a pain! It will go down from the console. Seeing's how no door function. But it will go up when I lock the doors! Thankx bud!!

[ptcruiser]

Taz,
I see your on the MB site as well as the 202. I think the whole window thing is doing resets to begin with. Start with a battery disconnect, wait for a few hours and reconnect and reset the windows as outlined in the owners manual.
If that doesn't work, then it's a one by one process to find the problem.
Eventually, everything can be solved.

[taz069]

Yeah pt I be a little everywhere. I mainly stick to this 202 club. When I do visit the other mb and benz world I try to find all the 202 peeps I can and lend a hand where I can. And I am sure to mention all the good folks here. Thanks for the 411 on the window reset will look it up. Be safe and have a happy 4th.

[atikovi]

Looks like I need to replace the window switch, but I will test it first.

You might be able to just take the switch apart and clean the contacts.

[taz069]

Now that is a great thought!! Break into that switch and clean the old factory contact goop out and lightly resurface the copper contact points. God i feel stupid now. Have done that a ton of times just didn't think of it. Thanks for the helpful tip for pt.

[atikovi]

Yea, on these older cars there are still some parts you can repair instead of having to replace.

[atikovi]

A fiberglass pencil like this works great for getting into tight spaces and cleaning off the metal contacts: http://www.mcmelectronics.com/product/DISTRIBUTED-BY-MCM-SABU10191-/SABU10191

[taz069]

HeHe!! I've always used the old trusty pocket knife. Just a lil scratching to clear up the old build up. And you can tell a dif when it is scrapped off!! The old dull color of brown turns shiney. Just call me low budget! I use what i have on hand. Also rubbing alcohol and q-tips work wonders!!

[strictlyspeakin]

I like your style Taz