Diagnostic Routine P

Diagnostic Routine P

Diagnostic Overview

The Blower Motor Does Not Operate Correctly

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

Normal Operation and Fault Conditions

Voltage is supplied to the relay coil from the BJB (Battery Junction Box) fuse 23 (5A) and relay switch contacts from the BJB (Battery Junction Box) fuse 10 (40A). When the blower motor relay coil receives a ground from the BCM (Body Control Module), the relay coil is energized and voltage is delivered to the blower motor. The HVAC (Heating, Ventilation, and Air Conditioning) module controls the ground for the blower motor. REFER to Blower Motor Resistor .

DTC Fault Trigger Conditions






Pinpoint Test

NOTICE: The following step uses a test light to simulate normal circuit loads. Use only the test light recommended in the Special Tools table at the beginning of this system. To avoid connector terminal damage, use the Flex Probe Kit for the test light probe connection to the vehicle. Do not use the test light probe directly on any connector.

1. CHECK THE BLOWER MOTOR OPERATION

1. Ignition ON.

2. Select all blower speed positions.

Does the blower motor operate in any position?






2. CHECK THE CIRCUIT BETWEEN THE BLOWER MOTOR AND THE BLOWER MOTOR RESISTOR FOR AN OPEN

1. Ignition OFF.

2. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C2357B.

3. Disconnect: Blower Motor.

4. Measure:





Is the resistance less than 1 ohms?






3. CHECK LOW CONTROL CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C2357B.

3. Disconnect: Blower Motor Resistor.

4. Measure:





Is the resistance less than 1 ohms?






4. CHECK BLOWER MOTOR RESISTOR AN OPEN

1. Measure:





Is the resistance approximately 2.5 ohms?






5. CHECK THE MED-LO CONTROL CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Disconnect: Blower Motor Resistor.

3. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C2357B.

4. Measure:





Is the resistance less than 1 ohm?






6. CHECK BLOWER MOTOR RESISTOR AN OPEN

1. Measure:





Is the resistance approximately 1.1 ohms?






7. CHECK THE MED-HI CONTROL CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Disconnect: Blower Motor Resistor.

3. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C2357B.

4. Measure:





Is the resistance less than 1 ohms?






8. CHECK BLOWER MOTOR RESISTOR AN OPEN

1. Measure:





Is the resistance approximately 0.3 ohm?






9. CHECK THE CIRCUIT BETWEEN THE BLOWER MOTOR AND THE BLOWER MOTOR RESISTOR FOR AN OPEN

1. Ignition OFF.

2. Disconnect: Blower Motor Resistor.

3. Disconnect: Blower Motor.

4. Measure:





Is the resistance less than 1 ohm?






10. CHECK BLOWER MOTOR CONTROL CIRCUITS FOR A SHORT TO GROUND

1. Ignition OFF.

2. Disconnect: Blower Motor Resistor.

3. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C2357B.

4. Measure:





Are the resistances greater than 10,000 ohms?






11. 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?