Diagnostic Routine R
Diagnostic Routine R
Diagnostic Overview
The Blower Motor Is Inoperative
Refer to Wiring Diagram Set 55 for schematic and connector information Electrical Diagrams.
Normal Operation and Fault Conditions
Voltage is supplied to the relay coil from BJB (Battery Junction Box) fuse 23 (5A) and relay switch contacts from 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 control module. Power and ground for the blower motor is provided by the blower motor speed control. The HVAC (Heating, Ventilation, and Air Conditioning) module sends a PWM (Pulse Width Modulated) signal to the blower motor speed control to control the blower speed.
DTC Fault Trigger Conditions
Visual Inspection and Diagnostic Pre-checks
- Inspect BJB (Battery Junction Box) fuses 10 (40A) and 23 (5A).
Pinpoint Test
1. CHECK THE BCM (Body Control Module) FOR DTCs (Diagnostic Trouble Codes)
1. Ignition ON.
2. Using a scan tool, perform BCM (Body Control Module) self-test.
Is DTC (Diagnostic Trouble Code) B10AF:13 or B10AF:19 received?
2. CHECK THE BLOWER MOTOR RELAY CONTROL CIRCUIT FOR AN OPEN
1. Ignition OFF.
2. Disconnect: Blower Motor Relay.
3. Disconnect: BCM (Body Control Module) C2280A.
4. Measure:
Is the resistance less than 3 ohms?
3. CHECK THE BLOWER MOTOR RELAY CONTROL CIRCUIT FOR A SHORT TO POWER
1. Ignition OFF.
2. Disconnect: Blower Motor Relay.
3. Disconnect: BCM (Body Control Module) C2280A.
4. Measure:
Is any voltage present?
4. CHECK THE BLOWER MOTOR RELAY SUPPLY VOLTAGES
1. Measure:
Are the voltages greater than 11 volts?
5. CHECK THE OPERATION OF THE BLOWER MOTOR WITH THE BLOWER MOTOR RELAY BYPASSED
1. Connect a fused jumper wire:
2. Ignition ON.
Does the blower motor operated correctly?
6. CHECK FOR POWER AT THE BLOWER MOTOR CONTROL
1. Connect: Blower Motor Relay.
2. Disconnect: Blower Motor Control C297A.
3. Ignition ON.
4. Measure:
Is the voltage greater than 11 volts?
7. CHECK THE POWER CIRCUIT BETWEEN THE BJB (Battery Junction Box) BLOWER MOTOR CONTROL MODULE FOR AN OPEN
1. Disconnect: Blower Motor Relay.
2. Measure:
Is the resistance less than 3 ohms?
8. CHECK THE POWER CIRCUIT BETWEEN THE BJB (Battery Junction Box) BLOWER MOTOR CONTROL MODULE FOR A SHORT TO GROUND
1. Disconnect: Blower Motor Control Capacitor (early production).
2. Measure:
Is the resistance greater than 10,000 ohms?
9. CHECK BLOWER MOTOR CONTROL GROUND FOR AN OPEN
1. Ignition OFF.
2. Measure:
Is the resistance less than 3 ohms?
10. CHECK FOR VOLTAGE TO THE BLOWER MOTOR
1. Ignition OFF.
2. Connect: Blower Motor Control C297A.
3. Disconnect: Blower Motor.
4. Ignition ON.
5. Select the highest blower motor setting.
6. Measure:
Is the voltage greater than 11 volts?
11. CHECK THE CIRCUITS TO THE BLOWER MOTOR FOR AN OPEN
1. Ignition OFF.
2. Disconnect: Blower Motor Control.
3. Measure:
Are the resistances less than 3 ohms?
12. CHECK THE BLOWER MOTOR CIRCUITS FOR A SHORT TOGETHER
1. Measure:
Is the resistance greater than 10,000 ohms?
13. CHECK THE BLOWER MOTOR CONTROL CIRCUIT FOR AN OPEN
1. Ignition OFF.
2. Disconnect: Blower Motor Speed Control C297A.
3. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228B.
4. Measure:
Is the resistance less than 3 ohms?
14. CHECK THE BLOWER MOTOR CONTROL CIRCUIT FOR A SHORT TO GROUND
1. Measure:
Is the resistance greater than 10,000 ohms?
15. CHECK THE BLOWER MOTOR CONTROL CIRCUIT FOR A SHORT TO POWER
1. Measure:
Is any voltage present?
16. CHECK FOR CORRECT BCM (Body Control Module) OPERATION
1. Ignition OFF.
2. Disconnect and inspect all the BCM (Body Control 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 BCM (Body Control 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?
17. 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?
