Diagnostic Routine E

Diagnostic Routine E

Diagnostic Overview

The Auxiliary Temperature, Mode, and Blower Motor Controls Are Inoperative Or Do Not Operate Correctly Using the Rear Auxiliary Controls Only

Refer to Wiring Diagram Set 52 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

Under normal operation, the rear auxiliary control is supplied a 5-volt reference and ground from the HVAC (Heating, Ventilation, and Air Conditioning) module. When the auxiliary blower motor speed, airflow mode or temperature control is adjusted, the HVAC (Heating, Ventilation, and Air Conditioning) module reads the voltage from the rear auxiliary climate controls on the auxiliary blower motor speed, airflow mode and temperature control feedback circuits to determine the requested setting.

DTC Fault Trigger Conditions






Pinpoint Test

1. CHECK THE CIRCUIT BETWEEN THE HVAC (Heating, Ventilation, and Air Conditioning) MODULE AND THE AUXILIARY CLIMATE CONTROL ASSEMBLY FOR A SHORT TO VOLTAGE

1. Ignition OFF.

2. Disconnect: Auxiliary Climate Control Assembly.

3. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228B.

4. Ignition ON.

5. Measure:





Is voltage present on any of the circuits?








2. CHECK THE CIRCUIT BETWEEN THE HVAC (Heating, Ventilation, and Air Conditioning) MODULE AND THE AUXILIARY CLIMATE CONTROL ASSEMBLY FOR A SHORT TO GROUND

1. Ignition OFF.

2. Measure:





Are the resistances greater than 10,000 ohms?








3. CHECK THE CIRCUIT BETWEEN THE HVAC (Heating, Ventilation, and Air Conditioning) MODULE AND THE AUXILIARY CLIMATE CONTROL ASSEMBLY FOR AN OPEN

1. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228B.

2. Measure:









Are the resistances less than 3 ohms?








4. CHECK FOR CORRECT HVAC (Heating, Ventilation, and Air Conditioning) MODULE OPERATION

1. Ignition OFF.

2. Disconnect and inspect all HVAC (Heating, Ventilation, and Air Conditioning) module connectors.

3. Repair:

- corrosion (install new connector or terminals- clean module pins)
- damaged or bent pins- install new terminals/pins
- pushed-out pins- install new pins as necessary

4. Reconnect the HVAC (Heating, Ventilation, and Air Conditioning) module connectors. Make sure they seat and latch correctly.

5. Operate the system and determine if the concern is still present.

Is the concern still present?