ATC Blower Motor Inoperative

Possible Causes:

• Open Junction Block Fuse
• Fused Ignition Switch Output Short To Ground
• Blower Motor Short To Ground
• Blower Motor Power Module Short To Ground
• Ground Circuit Open
• Fused Ignition Switch Output Circuit Open
• Blower Motor Control Circuit Short To Ground
• Body Control Module
• Blower Motor Operation
• Blower Motor Power Module Open

Testing

1. Turn ignition off. Remove and inspect the blower motor fuse No. 23 in the junction block. See Figure . If the fuse is open, go to next step. If the fuse is not open, go to step  5 .
2. Replace fuse No. 23 in junction block. Turn ignition on. Operate the blower motor in all speeds. Start the engine and operate the ATC system in all modes and speeds. Recheck the fuse. If the is open, go to next step. If the fuse is not open, see WIRING DIAGRAMS  to isolate a intermittent short to ground condition.
3. Turn ignition off. Disconnect blower motor power module harness connector. See Figure . Measure the resistance between ground and the fused ignition switch output circuit in the blower motor power module connector. If the resistance is 5 ohms or less, repair the fused ignition switch output circuit for a short to ground and replace the fuse. If the resistance is 5 ohms or more, go to next step.
4. Disconnect blower motor 2-way harness connector at the blower motor power module. Replace the junction block fuse No. 23. Connect a jumper wire between the fused ignition switch output circuit in the blower motor power module connector and the Dark Green wire in the blower motor connector. Connect a jumper wire between the ground circuit in the blower motor power module connector and the Black wire in the blower motor connector. Turn the ignition on. Listen to the blower motor for proper operation. If the blower motor operated at full speed without blowing the fuse, replace the blower motor power module. If the blower motor did not operate at full speed, replace the blower motor. See AUTOMATIC A/C-HEATER SYSTEMS - CONCORDE, INTREPID & 300M article in HVAC.
5. Turn ignition off. Disconnect blower motor power module harness connector. See Figure . Measure the resistance between ground and the ground circuit. If the resistance is 5 ohms or less, go to next step. If the resistance is 5 ohms or more, repair the ground circuit for an open.
NOTE: Ensure fuse No. 23 is installed in the junction block.
6. Turn ignition on. Using a 12-volt test light connected to ground, probe the fused ignition switch output circuit in the blower motor power module connector. If the test light illuminates, go to next step. If the test light does not illuminate, repair the fused ignition switch output circuit for an open.
7. Disconnect the BCM C2 harness connector. See Figure . Measure the resistance between ground and the blower motor control circuit. If the resistance is 5 ohms or less, repair the blower motor control circuit for a short to ground. If the resistance is 5 ohms or more, go to next step.
8. Reconnect the blower motor and the blower motor power module. Turn the ignition ON and observe the blower motor. If the blower motor is running at full speed, replace the BCM. See BODY CONTROL MODULE  under REMOVAL & INSTALLATION. If the blower motor is not running at full speed, go to next step.
9. Disconnect the blower motor 2-way harness connector at the blower motor power module. Connect a jumper wire between the fused switch output circuit in the blower motor power module connector and the Dark Green wire in the blower motor connector. Connect a jumper wire between the ground circuit in the blower motor power module connector and the black wire in the blower motor connector. Turn the ignition on. Listen to the blower motor for proper operation. If the blower motor operates at full speed, replace the blower motor power module. If the blower motor did not operate at full speed, replace the blower motor. See AUTOMATIC A/C-HEATER SYSTEMS - CONCORDE, INTREPID & 300M article in HVAC.