Well, crap.

Ok, forget testing it... I tried and fried it.

I found this on the forum... Followed it and sparks flew when I did poss to #4... Now the motor will not park. So don't use this information for a 87 300D.


Testing wiper motor

Warmblood58, before embarking in checking or replacing relay or switch, it is suggested you run the following test to ascertain whether your wiper motor is faulty.

Testing wiper motor

Disconnect the plug on top of the wiper motor and put it to one side.
On the motor there is the male plug connector with 5 pins (2 on the left and 3 on the right as per pics). Ignore sequence of pin No.1. Number them as follows:

From the left (there is only 2 pins) top left number 3 and bottom left number 5.
From the right (there is 3 pins) top number 2, middle number 4 and bottom number 6.
Using crocodile clips make following connections:

Connect a positive and negative line to the battery (or 12V source).
Clamp positive line to plug connector pin No.3 and negative line to pin No.6.
Connect an additional line to positive pole of battery and hold other end of this line against plug pin No.2, then 4 and then 5, one after another.

Pin no.2 actuates slow wiper motion
Pin no.4 actuates fast wiper motion
Pin no.5 actuates interval motion

If all above motions occur, your motor is fine and you need to find relay and switches for the fault as others have advised on earlier posts.