B10EB-14

B10EB-14-BLOWER MOTOR CONTROL - CIRCUIT SHORT TO GROUND OR OPEN





For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The A/C Heater Control constantly monitors the Blower Control circuit to the Blower Motor Power Module for proper operation. If the voltage or the Pulse Width Modulation (PWM) on that circuit drops below or rises above a predetermined value, a DTC will set. For further information .

- When Monitored:
With the ignition on.

- Set Condition:
If the A/C Heater control detects the Blower Motor Control circuit Pulse Width Modulation (PWM) is less than 0% and or greater than 100% or PWM equals 100% for the period of 30 seconds.





Always perform the HVAC Pre-Diagnostic Troubleshooting procedure before proceeding. .

Diagnostic Test

1. CHECK IF DTC IS ACTIVE
1. Ignition on, engine not running.
2. With the scan tool, read HVAC DTCs.

NOTE: It can take up to 30 seconds or more for this DTC to mature.

Is this DTC active?

Yes
- Go To 2

No
- Go To 6

2. CHECK THE (C56) BLOWER CONTROL CIRCUIT FOR A SHORT TO GROUND




1. Turn the ignition off to the lock position.
2. Disconnect the Blower Motor Power Module C1 harness connector
3. Disconnect the A/C Heater Control C1 harness connector.
4. Measure the resistance between ground and the (C56) Blower Control circuit.

Is the resistance below 100k Ohms?

Yes
- Repair the (C56) Blower Control circuit for an short to ground.
- Perform the HVAC VERIFICATION TEST. .

No
- Go To 3

3. CHECK THE (C56) BLOWER CONTROL CIRCUIT FOR AN OPEN




1. Turn the ignition off to the lock position.
2. Measure the resistance of the (C56) Blower Control circuit between the A/C Heater Control harness connector and the Blower Motor Power Module harness connector.

Is the resistance above 100k Ohms?

Yes
- Repair the (C56) Blower Control circuit for an open.
- Perform the HVAC VERIFICATION TEST. .

No
- Go To 4

4. CHECK THE (Z911) GROUND CIRCUIT FOR AN OPEN




1. Using a 12-volt test light connected to 12 volts, check the (Z911) Ground circuit.

NOTE: The test light must illuminate brightly. Compare the brightness to that of a direct connection to the battery.

Does the test light illuminate brightly?

Yes
- Repair the (Z911) Ground circuit for an open.
- Perform the HVAC VERIFICATION TEST. .

No
- Go To 5

5. CHECK THE BLOWER MOTOR POWER MODULE
1. Turn the ignition off to the lock position.
2. Replace the Blower Motor Power Module. .
3. Perform the HVAC VERIFICATION TEST. .

Did the DTC reset during or after the HVAC Verification Test?

Yes
- Replace and program the A/C Heater Control.
- Perform the HVAC VERIFICATION TEST. .

No
- Test complete.

6. CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set the DTC are not present at this time.
2. With the scan tool, check the Environmental Data to help identify the conditions in which the DTC was set.
3. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
4. Wiggle the wiring and connectors while checking for shorted and open circuits.

Were there any problems found?

Yes
- Repair as necessary.
- Perform the HVAC VERIFICATION TEST. .

No
- Test complete.