windscreen wiper w124 1989

[nickdub]

Hi,
The fromt wiper motor on my 250TD is not coming on at all.

so far I have :-
1) taken the #2 fuse out cleaned the contacts and switched it round (there is power getting to it, as I checked with a volt meter with the wiper switch on)
2) swapped the indicator stalk switch over for another secondhand one
3) swapped the relay # 201 821 00 47 for another second hand one

the only other known electrical problem on the car is the windows which sometimes work and sometimes not.

The wiper was working fine and showed no problems before it suddenly stopped responding.

Is the next place to check the relay contacts or can someone suggest other possible things to look at?

(There is another large relay # 126 542 03 32 but from what I've read that is nothng to do with the wiper - have I got that right)

Thanks

Nick

PS I did have a problem with the ignition switch so I swapped in a new barrel+ key which seems fine - the problem with the wiper occurred before the ignition switch issue so I'm assuming they are unrelated.

 

[Dec]

Hi Nick. Is there any sound from the motor when switched on?, check with the stalk turned to all the different speeds, you will need to open bonnet to hear it properly.

When wiper is turned to intermittent can you feel/hear the relay click every 7or so seconds, this picture is for a W202, yours may be similar, the relay is I think #2 in picture. As far as I know, the relay is involved only in the intermittent setting and is not involved in the other speeds.
Also the wiper motor plug is identified in the picture, is yours visible or if you can locate it and check for power at it.

I would suggest the stalk, but you have more or less ruled that out with a replacment.

As a last resort you could open the motor, See post #17

I don’t think the that windows are related to the problem, the are just on the way out, I have had to replace all 4 on mine in the past few years.

Dec

Edit;...In the small insert picture of the wiper motor you can see a white and a Green wire, don’t know if the will be the same colour as yours but these 2 wires go to the brushes, Green is Live + and White is Neutral - , if you trace these 2 wires back to the motor plug and put power to them, independently of the cars electrical system, with a battery charger, if the motor runs, it must be ok, so the fault must be elsewhere, perhaps the 3 switches as in the opened motor or perhaps striped gears.

 

[nickdub]

relay, motor etc

Hi Dec,
Thanks for the response

Can't dectect anything from the relay with the switch in any of the positions.

I had a look in the Haynes manual and it seems like you have to take virtually everything apart to get at the motor electric connector. ie the connector is underneath the motor which is under the plastic surrounds and you need to take the wiper arm off .... Obviously I'm not anxious to do all that if the fault lies elsewhere.

I notice the relay contatcs have been a cause of some people's problems - I'm wodering if I should check these next ? Not precisely sure I have got the right relay either - my layout is rather different to the one in your photo, with two largish oblong boxes parallel to one another at the top right as seen from the front.

Nick

 

[Dec]

Unfortunately we have different cars and I am not familiar with yours. It is definitely possible to feel/hear the relay every 7 seconds when the wiper is turned to intermittent position.

The relay dose sound suspect but if you cant find fault with it, then I think you are going to have to go in after the motor, this link is for a W202 but should help…http://members.lycos.nl/mbenz/windshield_wiper.htm

The motor is connected in two ways, either a plug as in my picture or a plug located near the relays, by the fuses, should be a 5 pin plug.

There is no need to take the wiper arm off, but it makes it easier to work on when it is off.

Dec

 

[Dec]

Any chance the second stalk might be suspect? You could have a look at it first, it would be easier than getting at the motor.
http://forums.mercedesclub.org.uk/showthread.php?t=38617


Dec

 

[nickdub]

Hi,
I guess I could have replaced one duff stalk with another, I'll take a look tomorrow to see if there's anything to suggest a problem.

The fact that it stopped working suddenly, ie without any problems that slowly got worse, is making me think loose electrical connection somewhere. The idea of taking lots of things apart in order to try and track it down is making me wonder is it time to take it to the garage !

Nick

 

[Dec]

It is very hard to diagnose something over the Internet, a good mechanic could figure it out in seconds, this is a typical problem the see all the time.

I would agree with your assessment regarding the sudden failure being a simple connection somewhere and if it were a “mechanical” problem there would probably have been warning signs leading up to the failure.

Sorry I can’t be of more help Nick, it could be something simple, starring you in the face, but where, is the problem!

Dec

 

[nickdub]

Hi,
finally meanness got the better of laziness and combined with dry weather I had a go at taking out the wiber motor etc for checking

Good news was that the motor worked with no problems - there is definitely no power getting to it with everything switched on though.

Bad new is I still have figured out what the fault is.

Could it be a problem with the ignition switch which I had to change - are ther any connections on there which I should check ?

Thanks

Nick

 

[Dec]

Hi Nick
Sorry, I don’t know much about the ignition switch, hopefully someone else can advise.
You seem to have tried everything, stalk fuse relay, perhaps opening the motor, if you haven’t already done so, to have a look, might not do any harm if you still have it out of the car. It will be similar to this.

Dec

 

[roofless]

try the multi pin socket the one the stalk plugs into you can open it up & you will see all the wires check for solder joints that have come loose i had the this with my horn after my wiper stalk was replaced my wipers worked but no horn had it in bits for 4 hours with a volt meter till i found the sod

 

[nickdub]

Hi,
Thanks for the suggestion on the socket - I think there must be a broken circuit somewhere just not sure where to look. Can anyone point me towards some info on which pins in the socket do what ?

Cheers

Nick

 

[roofless]

when its open all the wires are exsposed just have a prod at the solder joints if you find a fracture re solder as i did i think when you did the ignition you might have pulled the loom & any weak solder would fracture i think when i changed mine it was tight to pull the multi pin plug out hence the duff solder on the horn as it worked prior hope you get lucky this time

 

[nickdub]

Hi,
My wiring is a bit different as the ignition is in the centre of the dashboard not on the steering column.

I'm just wondering if the problem with the windows and the wiper could be related. Does anyone know whther some fault withtin the wiring assembly around the ignition switch could be the problem ? I replaced the ignition barrel for a new barrel and key but something alse could be broken within the electrical part of the set-up.

Anyone got any thoughts on this or do I start ringing up garages ?

Cheers

Nick

 

[roofless]

hi all the 124 models are the same and all the wiring run the same way its well worth looking at the socket the wiper stalk plugs into just slide it to one side & it pops of the steel brace bar then unclip the back to expose the wires & check the solders

 

[nickdub]

Thanks for that - will have a look next time we get a dry day and have a bit of time available - probably just before Christmas the way the weather is going