Smoke in the Cabin! W124 e220 (1994)

[CAT220]

My wife took the car to work this morning, 5 mins into her journey she notices smoke coming in to the cabin, so she stopped the car and got out the smoke stopped when she turned the engine off but from what she could see it was coming from around the windscreen wiper control arm. She drove the car back home and left it there, ive not had a chance to look at it but she did say the windscreen wiper arm had "stopped" working and she couldnt turn the wipers off without turning off the ignition. I'm hoping this is just a blown fuse, but surely the fuse should blow preventing any smoking etc? I've not had a chance to look at the car myself, i'll have a look tonight but though some of you may have experienced this in the past?

Cheers,
C

 

[MangoMan]

Could be wrong, but it sounds more serious that just a blown fuse. More like a blown wiper motor or relay.....

 

[MangoMan]

I would remove the Wiper Motor Fuse to stop it catching alight! And get it checked out at a Auto Electrician chop-chop.

 

[74merc]

Same thing happened my e320 coupe although the switch still works. It only smoked for a few seconds but I'm expecting it to fail anytime. I reckon it's a short circuit, hopefully someone can shed more light on it.

 

[CAT220]

I would remove the Wiper Motor Fuse to stop it catching alight! And get it checked out at a Auto Electrician chop-chop.

Cheers - Will do that tonight. Strange one that the wipers are still working.

 

[CAT220]

Cheers - Will do that tonight. Strange one that the wipers are still working.

Does anyone know what fuse it is?

 

[MangoMan]

Does anyone know what fuse it is?

Should be written on the inside of the Fuse Box Lid/Cover, They are all numbered.

Hope this helps.

 

[CAT220]

just realised that when I went out Donkey ears for moi! ;-)

The fuse is fine, I'm now thinking its the switch? When I start the car the wipers are on and I cant turn them off (obviously I could remove the fuse).

Cheers,
C

 

[Dieselman]

If the smoke definately came from the wiper unit this will be the park switch inside the gearbox has arced and burned.

Worth stripping and cleaning before condemning.

 

[Ted]

I'd go with what Dieselman says.
When a wiper motor parks, the park switch puts a short circuit across the windings of the motor - this makes it stop quickly.
If the park switch goes dodgy (technical term) this could short out the supply.

 

[television]

I'd go with what Dieselman says.
When a wiper motor parks, the park switch puts a short circuit across the windings of the motor - this makes it stop quickly.
If the park switch goes dodgy (technical term) this could short out the supply.

The motor does not work like that, , there is a cam on the wheel that opens the contacts in the park posistion, the stalk overides this switch, the wipers "on" switch overides the parking switch.
The reason it stops quickly is that it is a worm drive

 

[Dieselman]

The motor does not work like that, , there is a cam on the wheel that opens the contacts in the park posistion, the stalk overides this switch, the wipers "on" switch overides the parking switch.
The reason it stops quickly is that it is a worm drive

Agreed. Hence the word gearbox. All the wiper stalk/relay does is hit the motor with power when the switch is open circuit. If the switch fails open then that's when the wipers park anywhere as soon as turned off.

Cheers

 

[television]

I should have added that the fault is most likely to be the intermitant wipe relay, that is either on its own or part of the exoensive N10 relay dependent on the car.

Its an easy check to do, just pull the relay out and if the wiper stops, the fault is the relay.

Since the relay is sited near the motor the smoke will probaly have come from the relay.

This is when the motor runs all of the time

 

[CAT220]

Cheers for the replies guys....as you prob know already i'm not too clued up on the electrical workings. I was thinking if I renewed the stalk/switch then that would solve the problem, i'm assuming that the fact the wipers still operate albeit at one speed and on permanently due to the stalk not moving then the wiper motor must be ok. Please tell me if i'm talking cr*p.

Cheers,
C

 

[Ted]

I stand corrected, although this certainly used to be the case - including wipers with worm drives.
If you just remove the power, the motor will continue to spin under its own inertia.

 

[CAT220]

I should have added that the fault is most likely to be the intermitant wipe relay, that is either on its own or part of the exoensive N10 relay dependent on the car.

Its an easy check to do, just pull the relay out and if the wiper stops, the fault is the relay.

Since the relay is sited near the motor the smoke will probaly have come from the relay

ok, cheers, the car is a w124 e220 (1994). Does anyone know where the relay is?

Cheers,
C

 

[television]

The chances of this being the stalk is nill, remove the intermitant wipe relay first, and see if the motor still runs

 

[BlackC55]

I think its in the right hand fuse box at the back. You have to remove th complete cover.

 

[television]

http://www.detali.ru/cat/oem_mb2.as...GM=717.433&CT=F&cat=15S&SID=54&SGR=040&SGN=03


Item 78 in the link.

If you pull out this relay and the motor stops, it is the relay, cheapest ECP at £48

 

[Ted]

Perhaps I'm wrong, but the attached mercedes wiper schematic appears to agree with what I said....