'88 W124 all electric windows dead

[mark.porthouse]

Hi All,

I have a 300TE manufactured in the first half of 1988, which means it was before the electric window changes of 01/89.

None of the windows will wind up or down from any of the six switches.

Because of the age of the car it is from before the 'close windows on drivers door lock' function. I've always had to have the ignition key in and turned to operate the windows. They never operated with the ignition key out but the drivers door open.

At first the window operation was intermittent for about a week, then it went permanent. Only the windows are effected. The fuses are fine.

I assume that it is either the comfort diode, the window relay or the ignition switch.

I fiture that if it were the comfort diode or the ignition switch then other equipment would be adversely affected. So I conclude that it is the window relay.

The only info that I can find about the window relay (K6) location is that it is in position F in the middle line at the back of the relay box (nearest the firewall to the cabin). However, there is no relay there - so I'm left unsure as to where this relay might be.

Any thoughts?

Cheers,

Mark

 

[mark.porthouse]

I ought to have said that the car does have a sunroof (tilt and slide), which is unaffected and still works fine.
Mark

 

[mark.porthouse]

It occurred to me to swap around the two identical relays in the relay box behind the fuses and bingo: Identified.
The power windows relay is in position D (D is marked in the middle of the socket under the relay) as shown here:
http://www.autofuseboxdiagram.com/wp-content/uploads/2011/02/1986-1992-Mercedes-W124-ETMFuse-Box.jpg
This does not correspond with any location schemes I have seen anywhere.
The relay is a roughly cube shaped silver box with 5 pins. MB item no 0015420219.

I hope that this info is useful to someone at some point.

Cheers,

Mark

 

[mark.porthouse]

My last post wasn't quite correct. The relay is in position A, not D.

I note that since swapping over the relay certain items are powered with the ignition off when they weren't before. I.e. immobiliser doesn't switch on, power windows work, sunroof works, radio works.

Not sure why this is. I have swapped in three different relays, all with the same effect!