Solenoid Valve, Shut-Off Valve Heater Box Not Functioning

Solenoid Valve, Shut-off Valve Heater Box Not Functioning

Fault symptom
Solenoid valve, shut-off valve heater box not functioning

Diagnostic help
Certain markets have a vacuum-operated shut-off valve for the heater box.
Check that the coolant does not contain impurities.

Diagnostic procedure

1. Checking vacuum hoses
- Check vacuum hoses between shut-off valve and inlet pipe.

Are the hoses free from defects?
YES
- Proceed to step 2.
NO
- Rectify vacuum hoses.
- Proceed to step 4.






2. Checking power supply.
- Turn the ignition key to the ON position.






- Unplug the connector: Solenoid, heater box: (581).






- Connect a test lamp 86 11 857 between pin 1 in the female connector and a good grounding point.






- The test lamp should light up.

Tests OK?
YES
- Proceed to step 3.
NO
- Repair the lead in question.
- Proceed to step 4.






3. Checking ground lead
- Connect test lamp 86 11 857 between the pins 1 and 2 in the female connector.






- Turn the ignition key to the ON position.
- Activate the valve by turning both temperature controls to maximum cold.
- The test lamp should be off and light up when the valve is activated.

Tests OK?
YES
- Replace Solenoid, heat exchanger.
- Proceed to step 4.
NO
- Repair the lead in question.
- Proceed to step 4.






4. Final check
- Erase the diagnostic trouble codes from all systems.
- Check function.

Tests OK?
YES
- Actions taken to rectify problem were correct.
NO
- See Electronic Climate Control, Testing and Inspection.
Testing and Inspection