Terminal designation
- Terminal 31 - earth connection.
- Terminal 53 receives voltage for the first wiper speed.
- Terminal 53 a supplies positive current (+) for the final stage cleaner. The electric motor receives voltage through the sliding contact until the wiper comes to a rest position if the driver turns off the wiper.
- Terminal 53 b supplies voltage for the second wiper speed (additional winding).
- Via terminal 53 e, the wiper motor is braked when it returns after switching off so that it does not overshoot its initial position.
Checking the cleaner motor
First you need to check if the electric motor is damaged and if its power supply is good. This is done as follows:
1. Disconnect the connector from the motor.
2. Connect with two auxiliary cables (+) And (-) car battery with wiper motor terminals:
- lead the cable from the positive pole of the battery to terminal 53 or 53 b;
- connect the second cable from the negative pole of the battery to terminal 31 of the electric motor.
Since the BMW 3 Series 6-cylinder has a battery located in the luggage compartment, a positive lead and a reliable ground point in the engine compartment can be used, refer to Section Starting the engine from an auxiliary power source.
3. Now, depending on the terminal used, the wiper motor should rotate at the speed corresponding to stage I or II. If this does not happen, the electric motor or the corresponding stage is defective. Remove the electric motor, refer to Section Removal and installation of the electric motor / wiper rods.