W164 rear wiper fault

[Bez]

Hello

Please could you give me some advice on the following fault:

Rear wiper only moves in 90 degrees "steps" when set on intermittent. When on wash/wipe mode seems to behave normally.

Visual check of motor looks Ok. I have cleaned all electrical connections to motor and relay.

Attached photo of relay which is obviously not original!

Is the problem with the relay and it is just a case of replacement or should I check other parts of the circuit?

Many thanks

 

[Bez]

Update

Hi

I have substituted another relay and fault is still the same?

Any ideas?

Thanks

Marc

 

[Dec]

What do you do when it goes to 90°, do you switch off then on again, or, does it pause then proceed in its sweep?

Dec

 

[Bez]

rear wiper fault

Hi Dec

Thanks for your reply.

The wiper pauses then continues on its sweep in steps.

I have tried to attach link to you tube clipI made of it if that helps?

DBNYgtRGP9c


Cheers

Marc

 

[Bez]

Dec, try this link:

https://www.youtube.com/edit?o=U&video_id=DBNYgtRGP9c

 

[Dec]

How many sweeps to a wash/wipe mode?

Your link no work, mine seems ok.

Dec

https://www.youtube.com/watch?v=DBNYgtRGP9c

 

[Dec]

If you turn the wiper off, immediately after turning it on, will it continue its sweep cycle across the screen and return to its correct park position?

Will twiddling the wiper switch alter the wipers bad behaviour?

It looks like a relay that’s turning on every 4 seconds.

Dec

 

[Bez]

Hi Dec

Cheers for editing my you tube link.

5 sweeps on wash/wipe mode.

When turned immediately off then wiper stops at that point, does not continue on its sweep.

Twiddling switch does not alter performance.

You are correct the relay is switching every 4 secs.

Bit of a puzzle!?

Do you have any other ideas?

Many thanks

Marc

 

[Dec]

Inside a wiper motor there are tracks and switches, yours will not be the same as what’s pictured below but it will work in a similar way.
You could try cleaning up the tracks & switches and put a tiny amount of grease on the tracks, you can see, what I think might be brass /metal shavings on the tracks where the switches run… 2nd picture… perhaps this is causing a short of some kind.

You would have to remove the motor and mechanism to access the gearbox and worm drive as illustrated in the first picture, however, it all does sound like an electrical fault somewhere with the wiper electrics, am only suggesting opening the motor gearbox if you can’t find an alternate explanation for the fault.
After all, it’s not a major fault, so maybe wait and see if another explanation emerges or if it fixes itself.

Dec

 

[Bez]

Hi Dec

Thanks for the suggestions and the pictures, much appreciated. I will check through the circuits and wires again before venturing inside the motor.

You can progress the wiper by moving the stalk switch back and forth so all is not lost.

I wondered about spraying the stalk switch with some electrical contact cleaner to see if that would penetrate inside and help?? What do you think?

cheers

marc

 

[Dec]

You would have to open up the stalk switch to spray inside, I doubt that would be of use as that part of the switch is seldom used I would think, but no harm in trying, you would at least see what condition it is on the inside.

There is a lot of electronics inside them; I should think the inside of yours is more complicated than the W202 stalk pictured below.

Dec

 

[Bez]

Hi Dec

Thanks for the photo. Am i right in thinking that the inner sleeve just pushes forward towards the steering column to expose the internals?

Ta

Marc

 

[Dec]

I don’t know how yours comes apart, similar to the above picture I suppose.

See… https://www.google.ie/search?q=w164...=3WnyWOrBCuSOgAbQ6qKADw#imgrc=bwFE6ewnC5bNWM:
You need a strong thumb grip to wrestle the parts apart, yours look like it has 3 parts to it, when opened the right section should move towards the steering column and the middle section probably moves in the same way, the end cap probably stays where it is.

You can use a penknife to lever the sections apart but you will probably mark the soft plastic.

Dec

 

[Bez]

Thanks Dec for the link too.

I see within the link there are descriptions of replacing the combination switch stalk which may also be an option in the absence of a wiring or connection fault.

I'll see how I get on with double checking the circuits again.

Cheers

Marc