HVAC

900F-GLOW PIN CIRCUIT LOW (ZHZ)

For a complete wiring diagram Consult Diagrams/Electrical.

- When Monitored:
Whenever the module is awake.

- Set Condition:
When the Glow Pin circuit is shorted to ground.





Diagnostic Test

1. TEST FOR INTERMITTENT CONDITION
With the scan tool, record and erase DTC's
Turn the ignition on and wait 30 seconds.
Operate the Auxiliary Heater system.
With the scan tool, read DTC's.
Does the scan tool display this DTC as active?

Yes

- Go To 2

No

- The condition that caused this symptom is currently not present. Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also, inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals. Repair as necessary.
- Perform BODY VERIFICATION TEST - VER 1.Verification Tests

2. GLOW PIN
Disconnect the Warm Water Auxiliary Heating 2 Control Unit harness connectors.
With the scan tool, record and erase DTC's
Cycle the ignition from on to off three times.
Turn the ignition on.
Operate the Auxiliary Heater system.
With the scan tool, read DTC's.
Does the scan tool display this DTC as active?

No

- Replace the Glow Pin.
- Perform BODY VERIFICATION TEST - VER 1.Verification Tests

Yes

- Go To 3

3. GLOW PIN CIRCUIT SHORTED TO GROUND
Turn the ignition off.
Disconnect the Glow Pin harness connector.
Measure the resistance between Ground and the Glow Pin circuit.
Does the ohm meter read open circuit?

Yes

- Repair the Glow Pin circuit for a short to ground.
- Perform BODY VERIFICATION TEST - VER 1.Verification Tests

No

- Replace the Warm Water Auxiliary Heater 2 Control Unit.
- Perform BODY VERIFICATION TEST - VER 1.Verification Tests