W124 windows dead

[Palmer]

The rear left works, the remaining 3 dont. Ive checked fuses etc, is there any common issues with windows before i start ripping bits apart?

Chris

 

[merc85]

I had the switch assembly give up the ghost on one of my w126's

 

[Dec]

There is the convenience control module, it contains 8 relays, 4 to raise the windows and 4 to lower them, take a look at this… 1994 E320 Cabriolet Passenger Window Question - PeachParts Mercedes ShopForum

The convenience control module is under rear seat and looks like this… https://www.google.ie/search?q=w202...BigB#tbm=isch&q=w124+convenience+control+unit

Dec

 

[optimusprime]

I think you have a relay also for windows in fuse box .
'

 

[Palmer]

The switches do feel gritty and worn when you press them. Might order some new switches as a first call

 

[Dec]

It’s unlikely all 6 switches are faulty.
Try swapping over a good switch to the opposite side to see if that makes any difference.
See… Mercedes-Benz W124 Rear Door Panel Removal | 1986-1995 E-Class | Pelican Parts DIY Maintenance Article

Dec

 

[Palmer]

Switch didnt work.

The back left that does open works on the front controls but not the rear.

Also ive looked for convenience control module and its not there. There is the vac pump one side and just a few wires the other.

 

[Dec]

Surprised one window switch partly works if the convenience control module is missing.
Do all the wires have plugs still connected?

Dec

 

[Palmer]

Surprised one window switch partly works if the convenience control module is missing.
Do all the wires have plugs still connected?

Dec

Yeah all seems like it should be. The car is a 1989 if that makes any difference.

The module should be under the seat base on the passenger side? The vac pump is drivers side. Wouldnt be behind the back rest of the seats would it?

 

[hotrodder]

This thread suggests no convenience/comfort module is normal for earlier 124s http://www.mbclub.co.uk/forums/electronics/185651-w124-relay.html

It's American so can't trust the wiring diagrams in the power windows (82-0840) pdf but FWIW 82 Lights, Wipers, Radio, Antenna, Misc Body Electrics explains the difference between the early vs later diode vs small convenience k24 relay in the front fuse/relay box

I might be wrong but can't see how the k24 relay could take out most of the windows as it powers up the window/sunroof circuits either when the ign is on or a front door is open. As said in the 1st link the windows are switched earth and earlier cars had two front door shut switches (at least on the drivers side) instead of one

 

[Dec]

Yeah all seems like it should be. The car is a 1989 if that makes any difference.

The module should be under the seat base on the passenger side? The vac pump is drivers side. Wouldnt be behind the back rest of the seats would it?

Plenty of space under the seat so backrest unlikely.
Can you put up a picture of the "few wires" under the back seat?

Dec

 

[Palmer]

Doesnt seem to be many relays in the fuse box ha!

I had the door card off on the drivers side, i was expecting it to be all rust and crap but it was actually quite good. When i did my dodge ram windows it was rusty as hell and after drenching it in WD40 and moving the window up and down it started working again. This seems dead tho. You can hang off the window with the switch pressed and nothing happens. I can hear a click from behind the door card when you press the switch.

 

[wongl]

On my W201 I found that the thermal cut-out fuse had rotted and covered with rust due to the plastic membrane behind the door card being punctured allowing water to leak in behind the door card.

Once I replaced this with a similar part from Maplin the electric window started working normally again.

 

[Deadly Dave]

Have you checked the fuses ? They might not be blown but they erode at the ends where they make contact with the holders. Its worth changing the whole lot of them every few years.

 

[carat 3.6]

I can hear a click from behind the door card when you press the switch.

Pre facelift car's don't have the convenience module, the wiring is much simpler in these. If you can hear the motor click when the switch is pressed, it's just lack of use causing them to stick. I normally do the following...

Remove the door card, and disconnect the wiring to the motor itself. Next step using a jump pack, is to briefly give the motor wires a flash of 24v. Do this both ways by swapping the positive and negative wires, and 9 times out of 10 the window motor will jump back into life.

Grease the regulator teeth while you've got the doorcard off and they work like new.

 

[Palmer]

Pre facelift car's don't have the convenience module, the wiring is much simpler in these. If you can hear the motor click when the switch is pressed, it's just lack of use causing them to stick. I normally do the following...

Remove the door card, and disconnect the wiring to the motor itself. Next step using a jump pack, is to briefly give the motor wires a flash of 24v. Do this both ways by swapping the positive and negative wires, and 9 times out of 10 the window motor will jump back into life.

Grease the regulator teeth while you've got the doorcard off and they work like new.

There is no clicking. I cant see how to get the motor and regulator out with the window stuck up lol

 

[Palmer]

Done it, just gave it a whack and it came out eventually. Tried the battery and jump leads, done nothing lol so im presuming motor is dead?

 

[Codger49]

Did you use 24v as per Carat 3.6's post?

 

[Palmer]

Did you use 24v as per Carat 3.6's post?

I didnt have a jump pack used my mondeos battery lol. Presuming thats 24v?

 

[Codger49]

Car batteries are pretty much always 12v.