Terminal designations
- Terminal 31 - ground connection.
- Terminal 53 receives voltage for the first wiper speed.
- Terminal 53a supplies positive current (+) for the final stage of the wiper. The electric motor receives voltage via a sliding contact until the wiper comes to a resting position if the driver switches off the wiper.
- Terminal 53b supplies voltage for the second speed of the wiper (additional winding).
- Terminal 53e brakes the wiper motor when returning after switching off, so as not to go past the starting position.
Checking the wiper motor
First, you need to check whether the electric motor is damaged and whether its power supply is working properly. This is done as follows:
1. Disconnect the connector from the electric motor.
2. Connect the vehicle battery to the windshield wiper motor terminals using two auxiliary cables (+) and (-):
- connect the cable from the positive battery pole to terminal 53 or 53b;
- connect the second cable from the negative pole of the battery to terminal 31 of the electric motor.
Since the BMW 3 Series with 6-cylinder engine has the battery located in the luggage compartment, the positive terminal 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 motor or the corresponding stage is defective. Remove the motor, refer to Section Removal and installation the windshield wiper motor/rods.