w124 Window and Sunroof Switches not working when door closed

[alex.phayes]

I have a 1991 w124 (E) 250 D.

It has just developed a fault and I'm stumped. I have tried searching the forums but have not found any info on what could be the cause.

When the I open the door, with ignition off, the windows and sunroof open, close and operate as they should. However, when I close the door and turn the ignition on those switches go completely dead.

Also today the fuel guage decided to stop working, i'm thinking that it's a coincidence though.

If anybody can offer any suggestions I will be very grateful.
TIA,

 

[LastMinute]

Do your windscreen wiper and main beam work? If they don't, fuse 2 has probably blown. If they do, there must be a fault in the wiring from fuse 2 to the electric window relay (under the back seat). (There is a diode in there which may have failed. I've no idea exactly where it is, though.)

The fuel gauge fault is almost certainly unrelated. You're sure there's some fuel in the tank, I take it...

 

[Ian B Walker]

Do your windscreen wiper and main beam work? If they don't, fuse 2 has probably blown. If they do, there must be a fault in the wiring from fuse 2 to the electric window relay (under the back seat). (There is a diode in there which may have failed. I've no idea exactly where it is, though.)

The fuel gauge fault is almost certainly unrelated. You're sure there's some fuel in the tank, I take it...

Remember all that for tomorrow

 

[LastMinute]

Remember all that for tomorrow

Haynes manual, page 12·26. It's not "all just lines", you know...

 

[LastMinute]

Remember all that for tomorrow

On second thoughts - forget it. At least the bit about the electric window relay being under the back seat. It is, of course, in the relay box. The diode should be in there as well. Brooklands book, page 242.

To do: Work out what the black box with all the wires under the back seat is...

 

[Gollom]

Remember all that for tomorrow

And expand on it for Easter

 

[Gollom]

On second thoughts - forget it. At least the bit about the electric window relay being under the back seat. It is, of course, in the relay box. The diode should be in there as well. Brooklands book, page 242.

To do: Work out what the black box with all the wires under the back seat is...

Ha! Think I know this! :bannana: It's the thingummy for the central door locking jobbie! (someone posted about this very recently)

Ian. Remember the above

 

[LastMinute]

It's the thingummy for the central door locking jobbie!

That's the wotsit on the right-hand side. I'm thinking of the doodah on the left...

 

[Ian B Walker]

Ha! Think I know this! :bannana: It's the thingummy for the central door locking jobbie! (someone posted about this very recently)

Ian. Remember the above

I have a spare one waiting

 

[GIB3000]

Window fault

I found this post as I have exactly the same problem my windows only work when one of or both front doors are open (interior light on) my wipers are working and so is main beam.

I have checked the fuses and changed the comfort relay under the rear seat, still have the problem.

Am posting to see if any of you have the answer. I can hear a relay clicking when the interior light switch is operated is there any other control box thingies or jobies that link the Int. light and central locking?

 

[Frank O' Phile]

check fuse No.2.

If it isnt broke then just change it anyway, I had this last weekend.

http://www.mbclub.co.uk/forums/showthread.php?p=584159#post584159

 

[GIB3000]

Have just changed fuse 2 no change, I also changed fuse 1 as it was blown as soon as I turned the ignition on it blew again, I think the only thing on this circuit that not working is the rear wiper Could these faults be connected?

 

[grober]

Have just changed fuse 2 no change, I also changed fuse 1 as it was blown as soon as I turned the ignition on it blew again, I think the only thing on this circuit that not working is the rear wiper Could these faults be connected?

what model is your car?
on the w124 series fuse one 16A feeds the following
backrest adjuster
central locking
cigarette lighter
convenience module
glove box light
rear headrests
seat heater control module
radio/ICE
REAR WINDOW defrost**
rear window sunshade
rear window wash wipe
seatbelt extender (cabriolet only)
sunroof

If the fuse blows like that you may have a direct short to earth somewhere. wiring at the door hinges is often a problem but could be anywhere. You need to isolate each circuit one at a time to locate the fault.
ps you refer to the rear wiper from which I deduce you have an estate -the rear door locking mechanism is often faulty on these.

 

[GIB3000]

Thanks for the response grober My car is a E300 D Auto W124 Estate was advised that it is quite common for the rear wiper to have problems,

Have got the rear head lining down to check for any washer fluid leaks around the connections but there is nothing looking wet.

Will start the search for a wiring fault.

 

[bolide]

Thanks for the response grober My car is a E300 D Auto W124 Estate was advised that it is quite common for the rear wiper to have problems

I would disagree. The rear wiper motor is not a common point of failure in my experience

The rear wiper is fed via a relay inside the tailgate so fault-finding it would include listening for the click of the relay. This relay may also be the timer for the intermittent wipe - not sure

The wires that feed into the tailgate past the hinge are a point of failure, as is the washer pipe as you note

Nick Froome
www.w124.co.uk

 

[GIB3000]

Fuse 1 was the answer, as this was blowing as soon as you turned on the ignition I chose to sort this first, the answer was very obvious a Key for the old Garage Door which is now at the tip was left in the ashtray, the key had some how droped in to the cigarette lighter and was shorting out.

Removed the key and replaced the 16a fuse all problems were sorted windows, working and rear wiper also working.

Sometimes the most obvious problems are the worst to find!

 

[GIB3000]

Fuse 1 was the answer, as this was blowing as soon as you turned on the ignition I chose to sort this first, the answer was very obvious a Key for the old Garage Door which is now at the tip was left in the ashtray, the key had some how droped in to the cigarette lighter and was shorting out.

Removed the key and replaced the 16a fuse all problems were sorted windows, working and rear wiper also working.

Sometimes the most obvious problems are the worst to find!

 

[Frank O' Phile]

Glad you got it sorted and found the key (eeek) to the problem.

BTW are you sure it was fuse 1, as the row starts with fuse A, then 1, 2, 3, etc.

 

[GIB3000]

Yes it was Fuse 1, to the right of fuse A looking from the front of the car.

 

[Frank O' Phile]

Yes it was Fuse 1, to the right of fuse A looking from the front of the car.

Thanks, didn't mean to sound patronising, mine is a fuse 2 problem. I'm still getting reports from Mrs O' that the problem still happens for the briefest moments, so I'm buying new fuses and fitting them today.