B1072

B1072 - Rear Blower Control Request Input Circuit Low

For a complete wiring diagram, refer to.

• When Monitored: With the ignition on.

• Set Condition: If the A/C heater control detects voltage less than a calibrated value for a specified amount of time on the rear blower control 5 volt source circuit.






• This DTC must be active for the results of this test to be valid. Do not perform this test if this DTC is stored.

Test Step 1 - Verify the DTC is Active

• Turn the ignition ON.

• With the scan tool, erase A/C heater control DTCs.

• Turn the ignition OFF, wait 10 seconds, and turn the ignition ON.

• With the scan tool, read A/C heater control DTCs.

Does the scan tool display this DTC as active?

Yes

• Go to Test Step 2 => [ Test Step 2 - Check the Rear A/C Heater Control Switch ]

No

• Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also, inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals.

• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test

Test Step 2 - Check the Rear A/C Heater Control Switch

• Turn the ignition OFF.

• Disconnect the rear A/C heater control 8 way harness connector.

• Turn the ignition ON.

• Measure the voltage of the rear blower control 5 volt source circuit in the rear A/C heater control 8 way harness connector.

Was the voltage at least 5 volts?

Yes

• Replace the rear A/C heater control.

• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test

No

• Go to Test Step 3 => [ Test Step 3 - Check Rear Blower Control 5 Volt Source Circuit for
a Short to Ground ]

Test Step 3 - Check Rear Blower Control 5 Volt Source Circuit for a Short to Ground

• Turn the ignition OFF.

• Disconnect the A/C heater control C2 harness connector.

• Measure the resistance between ground and the rear blower control 5 volt source circuit in the rear A/C heater control 8 way harness connector.

Is the resistance less than 10k ohms?

Yes

• Repair the rear blower control 5 volt source circuit for a short to ground.

• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test

No

• Go to Test Step 4 => [ Test Step 4 - Check Rear Blower Control 5 Volt Source Circuit for
an Open ]

Test Step 4 - Check Rear Blower Control 5 Volt Source Circuit for an Open

• Measure the resistance of the rear blower control 5 volt source circuit between the A/C heater control C2 harness connector and the Rear A/C heater control 8 way harness connector.

Is the resistance more than 5.0 ohms?

Yes

• Repair the Rear blower control 5 volt source circuit for an open.

• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test

No

• Replace the A/C heater control.

• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test