Terminal designations
The electric motor has the following terminals:
- Terminal 31 is the ground connection (common to all electrical equipment of the vehicle).
- Terminal 53 receives voltage for the first wiper speed.
- Terminal 53a supplies current (+) to the extreme position of the windshield wiper. The electric motor receives voltage through the brush until the wiper returns to its original position when the driver switches off the windshield wiper.
- Terminal 53b supplies voltage for the second speed wiper (auxiliary winding).
- Terminal 53e brakes the electric motor when returning after being switched off, so that the windscreen wiper does not move past its parking position.
- Not always available: terminal 53c supplies power to the windshield washer pump.
Checking the electric motor
First, you need to find out what is defective, the electric motor or the lack of power. In this case, you need to act as follows:
(Material taken from a web resource MercedesMan.ru)
1. Disconnect the multi-pin connector from the electric motor.
2. Connect 2 auxiliary cables (+) and (-) from the vehicle battery to the windshield wiper motor:
- Run one cable from the positive battery terminal to terminal 53 or 53b.
- Connect the second cable from the negative terminal of the battery to terminal 31 of the electric motor.
3. Now the electric motor should switch on to stage I or II depending on the terminal used. If this does not happen, the electric motor or the corresponding stage is defective. Remove the electric motor.