GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2005 🢒 Rainier - 2WD 🢒 DTC 🢒 DTC B0150, B0433, or B3782

DTC Descriptors

DTC B0150 : Air Flow Position Feedback #3 Circuit Malfunction

DTC B0433 : Temperature Control #3 FeedBack Circuit Malfunction

DTC B3782 : Air Flow Control #10 Feedback Circuit Malfunction

Circuit/System Description

The actuators operate using 5 circuits. A 5-volt reference, low reference, signal circuit and two bi-directional 0 or 12 volt control circuits. The HVAC control module supplies a low reference and 5-volt reference to the potentiometer. The HVAC control module monitors the voltage drop across the potentiometer on the door position signal circuit. As the actuator door changes position the door position signal circuit voltage also changes. The two bi-directional control circuits enable the actuator to operate. Both circuits are set to 0 volts when the HVAC control module detects, from the feedback potentiometer, that the actuator is in the desired position. In order to move the actuator, the HVAC control module switches the appropriate control circuit to 12 volts.

    • DTC B0150 is for the auxiliary mode actuator
    • DTC B0433 is for the auxiliary air temperature actuator
    • DTC B3782 is for the auxiliary mode actuator

Conditions for Running the DTC
    • The ignition is ON.
    • The HVAC module is ON.

Conditions for Setting the DTC

The actual door position differs from the commanded door position by more than 4 counts or the HVAC control module detects the door position signal circuit is less than 3 counts or greater than 253 counts.

Action Taken When the DTC Sets

The control circuit is deactivated for the appropriate actuator.

Conditions for Clearing the DTC
    • The DTC becomes history when the HVAC control module no longer detects the condition that set the DTC.
    • The history DTC will clear after 100 fault-free ignition cycles.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

HVAC Connector End Views

Description and Operation

    •  Air Delivery Description and Operation
    •  HVAC Schematics

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Verification

Ignition ON, command the appropriate actuator in both directions with a scan tool. The scan tool door position parameter reading should be between 3 and 253 counts.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the appropriate actuator.
  2. Ignition OFF, test for less than 10 ohms between the low reference circuit terminal 1 and ground.
    3. ⇒If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 3 and ground.
    4. ⇒If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
    ⇒If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the HVAC control module.
  4. Verify the scan tool Door Position parameter is greater than 250 counts.
    5. ⇒If less than the specified range, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the HVAC control module.
  5. Install a 3A fused jumper wire between the signal circuit terminal 2 and the low reference circuit terminal 1. Verify the scan tool Door Position parameter is less than 3 counts.
    6. ⇒If greater than the specified range, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the HVAC control module.
  6. Ignition OFF, test for less than 10 ohms between the control circuit terminal 5 and ground.
    7. ⇒If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the HVAC control module.
  7. Ignition OFF, test for less than 10 ohms between the control circuit terminal 4 and ground.
    8. ⇒If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuit tests normal, replace the HVAC control module.
  8. Connect a test lamp between control circuit terminal 5 and control circuit terminal 4.
  9. Ignition ON, command the appropriate actuator door in both directions with a scan tool. The test lamp should turn ON and OFF when commanded in both directions.
    10. ⇒If the test lamp remains OFF during either of the commands, test for a short to ground on either control circuit. If the circuits test normal, replace the HVAC control module.
  10. If both circuits test normal, test or replace the actuator.

Repair Instructions
    •  Auxiliary Heater and Air Conditioning Control Module Replacement
    •  Mode Actuator Replacement - Console
    •  Auxiliary Mode Valve Actuator Replacement
    •  Auxiliary Temperature Valve Actuator Replacement