Rear Fan Pot Shorted (ATC)

REAR FAN POT SHORTED (ATC)





For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
With the ignition on.

- Set Condition:
If the Rear Fan Sense input A/D counts are less than 3 (0.059 volts).





Diagnostic Test

1. ACTIVE HVAC DTC(S) PRESENT
Turn the ignition on.
Using the scan tool, clear all HVAC DTC's.
Using the A/C Heater Control, operate the Rear Fan.
With the scan tool, check for DTCs.
Does the scan tool display this DTC as active?

Yes

- Go To2

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 the BODY VERIFICATION TEST - VER 1. Body Verification Test.

2. CHECK (C11) REAR FAN SENSE SUPPLY CIRCUIT FOR A SHORT TO GROUND




Turn the ignition off.
Disconnect the A/C Heater Control harness connector.
Disconnect the Rear Booster Fan Rear Control Switch harness connector.
Measure the resistance between ground and the (C11) Rear Fan Sense Supply circuit.
Does the ohm meter read open circuit?

Yes

- Go To 3

No

- Repair the (C11) Rear Fan Sense Supply circuit for a short to ground.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.

3. CHECK (C11) REAR FAN SENSE SUPPLY CIRCUIT FOR AN OPEN




Measure the resistance of the (C11) Rear Fan Sense Supply circuit between the A/C Heater Control harness connector and the Rear Booster Fan Rear Control Switch harness connector.
Does the ohm meter read open circuit?

Yes

- Repair the (C11) Rear Fan Sense Supply circuit for an open.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Go To 4

4. CHECK (C31) REAR FAN SENSE CIRCUIT FOR A SHORT TO GROUND




Measure the resistance between ground and the (C31) Rear Fan Sense circuit.
Does the ohm meter read open circuit?

Yes

- Go To 5

No

- Repair the (C31) Rear Fan Sense circuit for a short to ground.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.

5. CHECK FOR ACTIVE DTC WITH REAR BOOSTER FAN REAR CONTROL SWITCH DISCONNECTED
Reconnect the A/C Heater Control harness connector.
Turn the ignition on.
With the scan tool, read HVAC DTCs.
Does the scan tool display this DTC as active?

Yes

- Replace the A/C Heater Control.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Replace the Rear Booster Fan Rear Control Switch.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.