Wiring W124 Euro Headlight Wipers - different wiring?

[Tassie]

Hi folks;

As a result of a parking lot incident I am able to economically convert my 1989 300E from US spec to Euro spec headlights along with the Euro wipers. The headlight wiring conversion was easy but the Euro wiper conversion has a problem.

The problem is that the US spec wiring connecters have 4 pins for the left headlight wiper motor and 3 pins for the right headlight wiper motor. The Euro spec wiper motors have 4 pins for each connector for both wiper motors. See attached pictures. The wiper motors were sourced from a 1995 E320 cabriolet in California as I understood that all '94-'95 W124's have the same headlight wiper motors no matter if they were US spec or Euro spec.

The shop connected the wiring connectors anyhow but blew a fuse so the connector differences are not trivial. It appears that the differences in the wiring connector for the right headlight wiper motor is causing the problem but not entirely sure. Can anyone direct me on what the problem could be? Is there another part that is missing such as a relay or other electrical part? Is it possible that I bought the wrong headlight wiper motors?

I appreciate your assistance as I would like to get my car operational!

Many thanks,
Paul

[schumi]

It has been a long time since I messed with this issue but IIRC the Euro headlight wiper motors are different than the US version and you can't use the US motors with Euro lights.

[compu_85]

On the W126 anyway the motors are the same us vs euro, but there are two different gears inside that change the sweep. Electrically they are the same, and if you switch the sides they will still run fine, but the squirters won't fire anymore. (That's what the 4th pin is for). Is there a wiring diagram on the motors themselves? My W126 motors have that, with wire colors.

Perhaps look at the wiring diagram for a late W124 and compare it to your early car.

-Jason

[Tassie]

The new right headlight motor part number is 124-820-10-42 R. This is apparently the correct part according to several postings on this website.

The fuse that is affected is #3 (park lamp rt/tail lamp rt/ headlight cleaning unit).

Can anyone help with wiring diagrams?

Thanks,
Paul

[Tassie]

I found the wiring diagram! After reviewing the attached wiring diagram for this circuit, I wonder if the headlight washer relay was damaged somehow. At the time of the accident, it was dark and raining. After the accident I had to drive the car home with the broken headlight and headlight wiper severely damaged (bent shaft and cracked motor housing). I wonder if driving with the headlights on and using the windshield wiper triggered the headlight wiper to actuate. The washer pump motor had somehow been activated and emptied the entire washer fluid reservoir during the short drive home. So, it appears to me that the accident created some kind of short that activated the washer pump circuit. With this short and because one wiper motor was “locked” in place and couldn’t move - would this create a problem with the relay somehow? The relay is wired between the wiper motor and the fuse #3 (the one that blew).

Anything else I should check? How can I test the relay? Any other thoughts?

Thanks,
Paul

[Tassie]

The shop replaced the 8A fuse with a larger fuse and apparently everything works as it should. If the headlight wipers only work with a larger fused - does this indicate a damaged relay? Or perhaps the wiper motors are too old/worn? I am worried that the larger fuse will not protect some vital and expensive electronics.

Your comments will be appreciated as I really have no idea what risks I have with this larger fuse in place.

Thanks,
Paul