Test Point 9
Test point 9Motor of footwell /
defrost valve
Signal implausible
Fault code 28
Diagnosis conditions
No control module fault stored.
No fault with supply voltage (5 volts).
Signal implausible
1. Check footwell / defrost valve for smooth operation.
2. Unplug connectors A, B, C and D from the heating/air-conditioning control.
3. Unplug connector from footwell / defrost valve drive motor.
4. Connect ohmmeter to connector C 8 and drive motor
Connector pin 1.
Display: < 5 Ohms
Connect ohmmeter to connector B 10 and drive motor connector pin 2.
Display: < 5 Ohms
Connect ohmmeter to connector A 12 and drive motor connector pin 3.
Display: < 5 Ohms
Connect ohmmeter to connector D 11 and drive motor connector pin 4.
Display: < 5 Ohms
Connect ohmmeter to connector D 3 and drive motor connector pin 5.
Display: < 5 Ohms
5. Check wire from connector C 8 to drive motor pin 1 for short to B+ and short to ground.
6. Check wire from connector B 10 to drive motor pin 2 for short to B+ and short to ground.
7. Check wire from connector A 12 to drive motor pin 3 for short to B+.
8. Check wire from connector D 11 to drive motor pin 4 for short to B+ and short to ground.
9. Check wire from connector D 3 to drive motor pin 5 for short to B+ and short to ground.