Electrical Equipment

No Response from A/C Heater Control Module






For a complete wiring diagram, refer to.






Test Step 1 - Test for Intermittent Condition

• Turn the ignition on.

• Ensure the IOD fuse is installed and battery voltage is between 10.0 and 16.0 volts.

• With the scan tool, select ECU View.

• A red X will be next to the module that is not communicating, indicating that the module is not active on the bus network. A green check indicates that the module is active on the bus network.

Does the scan tool display a red X next to the module?

Yes

• Go to Test Step 2

No

• The no response condition is not present at this time. Using the wiring diagram/schematic as a guide, inspect the wiring for chafed, pierced, pinched, and partially broken wires and the wiring harness connectors for broken, bent, pushed out, and corroded terminals.

Test Step 2 - Fused B(+) Circuit Open or Shorted






• Turn the ignition off.

• Disconnect the cluster C1 and C2 harness connectors.

• Using a test lamp connected to ground, check each fused B(+) circuit.

Does the test lamp illuminate brightly for each circuit?

Yes

• Go to Test Step 3

No

• Repair the fused B(+) circuit for an open or short.

• Perform the Body Verification Test. Refer to => [ Body Verification Test ] Body Interior.

Test Step 3 - Ground Circuit Open






• Using a test lamp connected to 12 volts, check the ground circuit.

Does the test lamp illuminate brightly for each circuit?

Yes

• Go to Test Step 4

No

• Repair the ground circuit for an open.

• Perform the Body Verification Test. Refer to => [ Body Verification Test ] Body Interior.

Test Step 4 - Fused Ignition Switch RUN/ACC Circuit Open or Shorted






• Turn the ignition on.

• Using a test lamp connected to ground, check the fused ignition switch RUN/ACC circuit.

Does the test lamp illuminate brightly?

Yes

• Go to Test Step 5

No

• Repair the fused ignition switch RUN/ACC circuit for an open or short.

• Perform the Body Verification Test. Refer to => [ Body Verification Test ] Body Interior.

Test Step 5 - CAN C Interior Bus Circuit Open






• Measure the resistance of the CAN C interior bus (-) 125K circuit between the totally integrated power module C7 harness connector and the HVAC harness connector.

• Measure the resistance of the CAN C interior bus (+) 125K circuit between the TIPM C7 harness connector and the HVAC harness connector.

Is the resistance less than 5.0 ohms on both circuits?

Yes

• Replace the A/C heater control module.

• Perform the Body Verification Test. Refer to => [ Body Verification Test ] Body Interior.

No

• Repair the CAN C interior bus 125K circuit for an open. Inspect the connector for damage.

• Perform the Body Verification Test. Refer to => [ Body Verification Test ] Body Interior.