Manual Temperature Control
B1052 - Rear Blend Door Control Circuit/Performance
For a complete wiring diagram, refer to.
Theory of Operation
The A/C heater control drives the rear mode door actuator via the rear mode door driver circuit and the rear common door driver circuit. The A/C heater control drives the rear blend door actuator via the rear blend door driver circuit and the common door driver circuit.
• When Monitored: With the ignition on.
• Set Condition: If the A/C heater control detects a short on the rear mode door driver circuit, the rear blend door driver circuit, or the rear common door driver circuit while attempting to drive the rear mode door actuator or the rear blend door actuator
• 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 - Check Rear Mode Door Driver Circuit, Driver Blend Door Driver Circuit, Rear Blend Door Driver Circuit, and C34 Common Door Driver Circuit for a Short to Voltage
• Turn the ignition OFF.
• Disconnect the A/C heater control C1 harness connector.
• Turn the ignition ON.
• Measure the voltage of the rear mode door driver circuit in the A/C heater control C1 harness connector.
• Measure the voltage of the driver door driver circuit between ground and the A/C heater control C1 harness connector.
• Measure the voltage of the rear blend door driver circuit in the A/C heater control C1 harness connector.
• Measure the voltage of the common door driver circuit in the A/C heater control C1 harness connector.
Is the voltage less than 0.2 volts for all measurements?
Yes
• Go to Test Step 2 => [ Test Step 2 - Check Rear Mode Door Driver Circuit, Driver Blend Door
Driver Circuit, Rear Blend Door Driver Circuit, and Common Door Driver
Circuit for a Short to Ground ]
No
• Repair the circuits with voltage more than 0.2 volts for a short to voltage.
• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test
Test Step 2 - Check Rear Mode Door Driver Circuit, Driver Blend Door Driver Circuit, Rear Blend Door Driver Circuit, and Common Door Driver Circuit for a Short to Ground
• Turn the ignition OFF.
• Measure the resistance of the rear mode door driver circuit between ground and the A/C heater control C1 harness connector.
• Measure the resistance of the driver door driver circuit between ground and the A/C heater control C1 harness connector.
• Measure the resistance of the rear blend door driver circuit between ground and the A/C heater control C1 harness connector.
• Measure the resistance of the common door driver circuit between ground and the A/C heater control C1 harness connector.
Is the resistance more than 10k ohms for all measurements?
Yes
• Go to Test Step 3 => [ Test Step 3 - Check Rear Mode Door Driver Circuit for a Short to
Other Door Driver Circuits ]
No
• Repair the circuits with a resistance less than 10k ohms for a short to ground.
• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test
Test Step 3 - Check Rear Mode Door Driver Circuit for a Short to Other Door Driver Circuits
• Measure the resistance between the rear mode door driver circuit and the rear blend door driver circuit, the recirculation door driver circuit, the common door driver circuit, the common door driver 2 circuit, and the mode door driver circuit in the A/C heater control C1 harness connector.
Is the resistance more than 100 ohms for all measurements?
Yes
• Go to Test Step 4 => [ Test Step 4 - Check Rear Blend Door Driver Circuit for a Short to
Other Door Driver Circuits ] .
No
• Repair the circuits with a resistance less than 100 ohms for a short together.
• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test
Test Step 4 - Check Rear Blend Door Driver Circuit for a Short to Other Door Driver Circuits
• Measure the resistance between the rear blend door driver circuit, the recirculation door driver circuit, the common door driver circuit, the common door driver 2 circuit, the mode door driver circuit, and the driver blend door driver circuit in the A/C heater control C1 harness connector.
Is the resistance less than 100 ohms for all measurements?
Yes
• Go to Test Step 5 => [ Test Step 5 - Check Common Door Driver Circuit for a Short to Other
Door Driver Circuits ]
No
• Repair the circuits with a resistance less than 100 ohms for a short together.
• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test
Test Step 5 - Check Common Door Driver Circuit for a Short to Other Door Driver Circuits
• Measure the resistance between the common door driver circuit and the recirculation door driver circuit, the common door driver 2 circuit, the mode door driver circuit, and the blend door driver circuit in the A/C heater control C1 harness connector.
Is the resistance more than 100 ohms for all measurements?
Yes
• Go to Test Step 6 => [ Test Step 6 - Check Rear Mode Door Actuator Circuit Resistance ]
No
• Repair the circuits with a resistance less than 100 ohms for a short together.
• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test
Test Step 6 - Check Rear Mode Door Actuator Circuit Resistance
• Measure the resistance between the rear mode door driver circuit and the common door driver circuit in the A/C heater control C1 harness connector.
Is the resistance between 30 and 40 ohms?
Yes
• Go to Test Step 7 => [ Test Step 7 - Check Rear Blend Door Actuator Circuit Resistance ]
No
• Replace the rear mode door actuator.
• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test
Test Step 7 - Check Rear Blend Door Actuator Circuit Resistance
• Measure the resistance between the rear blend door driver circuit and the common door driver circuit in the A/C heater control C1 harness connector.
Is the resistance between 30 and 40 ohms?
Yes
• Go to Test Step 8 => [ Test Step 8 - Run the Actuator Calibration Test ]
No
• Replace the rear blend door actuator.
• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test
Test Step 8 - Run the Actuator Calibration Test
• Reconnect the A/C heater control C1 harness connector.
• Turn the ignition ON.
• With the scan tool, erase HVAC DTCs.
• Turn the ignition OFF, wait 10 seconds, and then turn the ignition ON.
• With the scan tool, select system tests and then select actuator calibration test. When the test is complete, select view DTCs.
Does the scan tool only display B1052 - Rear Blend Door Control Circuit/Performance?
Yes
• Replace the A/C heater control.
• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test
No, Other DTCs Displayed
• Diagnose and repair the other DTCs. Refer to the table of contents in this section for a complete list of all HVAC related symptoms.
No, and No Other DTCs Displayed
• Using the wiring diagram as a guide, inspect the wiring and connectors for conditions causing an intermittent short. Repair as necessary.
• Perform the HVAC Verification Test. Refer to => Non-DTC Based Diagnostics. HVAC Verification Test