Motor Checks

The vehicle has many comfort devices and accessories driven by small servo motors. Examples include power windows, sunroof sliding panel, and central locking. Electric motors are switched on by switches, in most cases manually.

INSPECTION

1. Check the fuse of the corresponding electric motor. Replace it if necessary.

* Power window and sunroof motors have a circuit breaker that trips on overload and resets after a while. Before reactivating the device, eliminate the cause of the overload. Causes may be ice on the glass or contamination of the window guides.

2. If the fuse blows immediately, there is a short circuit.
3. To determine whether the electric motor is faulty, connect two battery cables to it. Connect the positive battery cable to the positive motor terminal and the negative cable to the negative terminal.
Polarity can be determined from the wiring diagram. It may be necessary to remove the electric motor. The supply voltage of all electric motors on the vehicle is 12–14 V. If the motor works after removal, the fault was in the power supply.

* A reduction in motor rotational speed or intermittent operation may be caused by worn brushes. In this case, replace the brushes.

4. Check the electric motor operation using the wiring diagram. Check the connection and the power wire.
5. Check for voltage on the live cable of the electric motor with a test lamp. The electric motor draws a high current, so a standard incandescent bulb can be used for testing. Such a test lamp has ordinary probes that can pierce the connecting cable. In this way, the presence of voltage can be checked quite simply.

The electric motor connection terminals are designated as follows:
Terminal 32 — ground connection
Terminal 33 — positive contact

Reversible electric motors, for example power window motors, have two positive connections. They are designated as follows:
Terminal 33L — left rotation connection
Terminal 33R — right rotation connection

* The wiper motor has a special contact designation, see the corresponding Section.

6. If there is no voltage at the electric motor, the cause may be in the power wire. Check the power wire according to the wiring diagram. Due to the high current, electric motors usually have an additional activation relay, see the corresponding Section.
7. If the fault has not been found, check the switch.
8. If any cable is damaged, it is advisable to replace it.