Checking the technical condition
1. Turn on the ignition.
2. Manually change the position of the control switch and measure the voltage between terminals 1 and 2 of the fan motor.
3. Move the control switch to the position where the voltage increases to the level corresponding to the maximum rotation speed.
4. If the measured voltage value does not correspond to the technical specifications, replace the power transistor with a known good one and check for correct operation.
5. If the problem is resolved, replace the power transistor.
Replacement
1. Disconnect the negative battery terminal.
2. Disconnect the connector (A) of the power transistor, unscrew the mounting screws and remove the power transistor (B).
3. Installation is carried out in the reverse order of removal.