Diagnostic Routine N

Diagnostic Routine N

Diagnostic Overview

The Temperature Control is inoperative or Does Not Operate Correctly

Refer to Wiring Diagram Set 54 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

REFER to Temperature Blend Door Actuator .

During an actuator calibration cycle, the HVAC (Heating, Ventilation, and Air Conditioning) module drives the temperature blend door until the door reaches both internal stops in the HVAC (Heating, Ventilation, and Air Conditioning) case. If the temperature blend door is temporarily obstructed or binding during a calibration cycle, the HVAC (Heating, Ventilation, and Air Conditioning) module can interpret this as the actual end of travel for the door. When this condition occurs and the HVAC (Heating, Ventilation, and Air Conditioning) module commands the actuator to its end of travel, the airflow may not be the expected temperature.

Pinpoint Test

1. CHECK THE TEMPERATURE BLEND DOOR ACTUATOR CIRCUITS FOR AN OPEN

1. Ignition OFF.

2. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C2357A.

3. Disconnect: Temperature Blend Door Actuator.

4. Measure:





Are the resistances less than 3 ohms?






2. CHECK THE TEMPERATURE BLEND DOOR ACTUATOR CIRCUITS FOR A SHORT TO GROUND

1. Measure:





Are the resistances greater than 10,000 ohms?






3. CHECK THE TEMPERATURE BLEND DOOR ACTUATOR CIRCUITS FOR A SHORT TO POWER

1. Ignition ON.

2. Measure:





Is any voltage present?






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

1. Ignition OFF.

2. Disconnect and inspect all the 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?