B1078

B1078-REAR BLOWER CONTROL CIRCUIT OPEN





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

Theory of Operation

The Totally Integrated Power Module (TIPM) works in conjunction with the A/C Heater Control to control the rear blower motor. The TIPM grounds the coil of the Rear Blower Motor Relay when rear blower motor operation is requested by the A/C Heater Control. The Rear Blower Motor Relay then provides battery voltage to the Rear A/C Heater Control. For additional information, Description and Operation.

- When Monitored:
With the ignition on.

With the Rear Blower Motor off.

- Set Condition:
When the Totally Integrated Power Module (TIPM) detects a low condition.





1. INTERMITTENT CONDITION
1. Turn the ignition on.
2. With the scan tool, clear all DTCs.
3. With the scan tool read DTCs.

Does the scan tool display DTC: B1078-REAR BLOWER CONTROL CIRCUIT OPEN?

Yes

- Go To 2

No

- Test complete, the condition or conditions that originally set this DTC are not present at this time. 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.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

2. CHECK THE REAR BLOWER MOTOR RELAY
1. Turn the ignition off.
2. Remove the Rear Blower Motor Relay and substitute it with a known good relay.
3. Turn the ignition on.
4. With the scan tool, clear all DTCs.
5. With the scan tool, read the DTCs.

Does the scan tool display DTC: B1078-REAR BLOWER CONTROL CIRCUIT OPEN?

Yes

- Go To 3

No

- Replace the Rear Blower Motor Relay.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

3. CHECK THE (L124) REAR BLOWER MOTOR RELAY CONTROL CIRCUIT FOR AN OPEN
1. Turn the ignition off.
2. Disconnect the TIPM C4 harness connector.
3. Remove the Rear Blower Motor Relay.
4. Measure the resistance of the (L124) Rear Blower Motor Relay Control circuit between the TIPM C4 harness connector and the Rear Blower Motor Relay.

Is the resistance below 5.0 Ohms?

Yes

- Go To 4

No

- Repair the open in the (L124) Rear Blower Motor Relay Control circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

4. CHECK THE (L124) REAR BLOWER MOTOR RELAY CONTROL CIRCUIT FOR A SHORT TO GROUND




1. Measure the resistance between ground and the (L124) Rear Blower Motor Relay Control circuit.

Is the resistance above 10k Ohms?

Yes

- Go To 5

No

- Repair the short to ground in the (L124) Rear Blower Motor Relay Control circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

5. CHECK THE (W24) COIL RELAY SUPPLY CIRCUIT FOR AN OPEN
1. Disconnect the TIPM C3 harness connector.
2. Measure the resistance of the (W24) Coil Relay Supply circuit between the TIPM C3 harness connector and the Rear Blower Motor Relay.

Is the resistance below 5.0 Ohms?

Yes

- Go To 6

No

- Repair the open in the (W24) Coil Relay Supply circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

6. CHECK THE (W24) COIL RELAY SUPPLY CIRCUIT FOR A SHORT TO GROUND




1. Measure the resistance between ground and the (W24) Coil Relay Supply circuit.

Is the resistance above 10k Ohms?

Yes

- Replace the TIPM. Totally Integrated Power Module (TIPM) - Removal.
- Perform the BODY VERIFICATION TEST. Body Verification Test.

No

- Repair the short to ground in the (W24) Coil Relay Supply circuit.
- Perform the BODY VERIFICATION TEST. Body Verification Test.