Intermittent electric windows issue on 97 W202, one not working at all.

[charlysays]

Very annoying fault here... noticed it the other night! Any help much appreciated!

The rear left window has completely and consistently stopped working from the switches on the centre console, not tried the door switch yet but I'm sure that'll be dead too.
The other three windows intermittently work fine as a group but take atleast 5 minutes to start working after switching the car on and will randomly drop out for a few minutes at a time, then be working fine again.

Hopefully unconnected by the wiper got stuck midway across the screen the other day too. I've greased the mech and its still working fine. Also the other night when I was leaving a car park I noticed the right indicator drop out a couple of times. Checked alternator output and there's 13.94v across the battery at idle so it doesn't look like a low voltage issue.

As of today, just this annoying elec window issue. I've got two or three donor cars (two are of the same year etc) so I can swap out parts no worries.

Many thanks

 

[grahamcol]

I wonder if damp is getting into the fuse box somehow. I'd start by lifting the lid and having a look. Doubtless others will post shortly with further ideas.

 

[John Laidlaw]

Assume you’ve done the window reset thing?

 

[LostKiwi]

Assume you’ve done the window reset thing?

Can't do it if the window won't move!

As above I'd check the fuse box. What type of fuses does it use?

 

[John Laidlaw]

Can't do it if the window won't move!

As above I'd check the fuse box. What type of fuses does it use?

Fair point well made- but would not the windows which work being reset jar the system to life? Just a crepe thought but as you say and Grahamcol probably fuses is a good place to start

 

[robparker]

Have a dig under the passenger well front sill cover, dig out the can connector.. if any signs of green, replace it. About £2 from Merc and will cause loads of electrical gremlins

 

[robparker]

Search for "w202 electric window fault cured". I uploaded some pics on that thread

 

[brianbrian]

If you have the parts, try changing the relay, under rear seat n,side, also take the door card of and put a live and earth to the window motor wires.

 

[star]

As rob said or try disconnecting one window motor at a time, start with the non working one 1st. I suspect it’s a can interference problem.

 

[charlysays]

Thanks guys, much appreciated. I'll try all this tomorrow!
Funnily enough re CAN interference... I have another one of these and it arrived to me with one rear elec window not working- previous owner said none were working but the other three were then reliable once the dodgy door was disconnected.
I'll check the CAN plug tomorrow and disconnect the dodgy door and see how it goes. If they stop playing up I'll swap out all the electronic gubbins from one of my donor cars.
Thanks again.