NO RESPONSE FROM HVAC (A/C HEATER CONTROL MODULE)

For a complete wiring diagram, refer to the Wiring Information.

Possible Causes
(A417) FUSED B (+) CIRCUIT OPEN OR SHORTED
(Z916) GROUND CIRCUIT OPEN
(F921) FUSED RUN RELAY OUTPUT CIRCUIT OPEN OR SHORTED
(D264) AND (D265) CAN INTERIOR BUS (125K) CIRCUITS OPEN
A/C HEATER CONTROL MODULE (HVAC)

1. TEST FOR INTERMITTENT CONDITION

NOTE: Check for any TSB(s) related to the condition. If a TSB applies, perform the procedure outlined in the TSB before continuing.

1.	Turn the ignition on.

NOTE: Make sure the IOD fuse is installed and battery voltage is between 10.0 and 16.0 volts.

2.	With the scan tool, read the module status.

NOTE: Check the TIPM for any active CAN hardware DTCs, perform DTC before proceeding.

Does the scan tool indicate that the module is active on the bus?

Yes

The no response condition is not present at this time. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.

Go To 2

2. CHECK THE (A417) FUSED B (+) CIRCUIT FOR AN OPEN OR SHORT

1.	Turn the ignition off.

2.	Disconnect the A/C Heater Control C1 harness connector.

3.	Using a 12-volt test light connected to ground, check the (A417) Fused B (+) circuit.

Does the test light illuminate brightly?

Yes

Go To 3

Repair the open or short in the (A417) Fused B (+) circuit.
Perform the BODY VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure).

3. CHECK THE (Z916) GROUND CIRCUIT FOR AN OPEN

1.	Using a 12-volt test light connected to 12-volts, check the (Z916) Ground circuit.

Does the test light illuminate brightly?

Yes

Go To 4

Repair the open in the (Z916) Ground circuit.
Perform the BODY VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure).

4. CHECK THE (F921) FUSED RUN RELAY OUTPUT CIRCUIT FOR AN OPEN OR SHORT

1.	Turn the ignition on.

2.	Using a 12-volt test light connected to ground, check the (F921) Fused Run Relay Output circuit.

Does the test light illuminate brightly?

Yes

Go To 5

Repair the open or short in the (F921) Fused Run Relay Output circuit.
Perform the BODY VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure).

5. CHECK THE (D265) AND (D264) CAN INTERIOR BUS (125K) CIRCUITS FOR AN OPEN

1.	Disconnect the TIPM C7 harness connector.

2.	Measure the resistance of the (D264) CAN Interior Bus (-) (125K) circuit between the TIPM C7 harness connector and the A/C Heater Control Module C1 harness connector.

3.	Measure the resistance of the (D265) CAN Interior Bus (+) (125K) circuit between the TIPM C7 harness connector and the A/C Heater Control Module C1 harness connector.

Are the resistances below 5.0 Ohms?

Yes

Replace the A/C Heater Control Module in accordance with the Service Information.
Perform the BODY VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure).

Repair the open in the (D265) or (D264) CAN Interior Bus (125K) circuit. Inspect the connector for damage.
Perform the BODY VERIFICATION TEST. (Refer to 28 - DTC-Based Diagnostics/MODULE, Totally Integrated Power (TIPM) - Standard Procedure).

NO RESPONSE FROM HVAC (A/C HEATER CONTROL MODULE)

Possible Causes