GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2000 🢒 Regal 🢒 DTC 🢒 DTC B0363 Left Actuator Feedback Open

Object Number: 598765 Size: SF
HVAC Components
Temperature Actuators
Temperature Controls
Handling Electrostatic Discharge Sensitive Parts Notice

Circuit Description

The heater-A/C control receives a left electric actuator position signal from the left electric actuator. The left electric actuator position sensor is a potentiometer that is tied to a 5V source through circuit 1217 (PNK/BLK) band to ground through circuit 61 (YEL), both from the heater-A/C control. The variable output from the potentiometer feeds back a position signal through circuit  1218 (BRN/WHT) to a pull-up resistor in the heater-A/C control. This signal relates to the position of the left electric actuator. This signal is used in order to determine the necessary drive signal to the left electric actuator motor in order to provide the proper air mix door position.

Conditions for Setting the DTC

The heater-A/C control performs an internal check on the left electric actuator position and determines that circuit 1218 (BRN/WHT) is open.

Action Taken When the DTC Sets

The heater-A/C control stores DTC B0363 in memory.

Conditions for Clearing the DTC
    • An open is no longer present in circuit 1218 (BRN/WHT).
    • Under all fault conditions, the ignition switch must be cycled from on to off, back to on before this DTC can change from current to history.
    • A history DTC will clear after 100 drive cycles if the condition for this malfunction is no longer present.
    • Using a scan tool

Diagnostic Aids

Check for an open in circuit 61 (YEL) or circuit 1218 (BRN/WHT). An open in these circuit may cause this DTC to set.

Test Description

The number(s) below refer to the step number(s) on the diagnostic table.

  1. This test checks if the heater-A/C control 5V supply is getting through circuit 1218 (BRN/WHT) .

    2.

  2. This test checks if the heater-A/C control ground is getting through circuit 6(YEL)1.

Step

Action

Value(s)

Yes

No

1

Was the heater-A/C control diagnostic system check performed?

--

Go to Step 2

Go to Diagnostic System Check

2

  1. Turn the ignition switch off.
  2. Disconnect the LH electric actuator electrical connector.
  3. Turn the ignition switch ON with the engine off.
  4. Use a digital multimeter (DMM) (J-39200) to measure the voltage between the LH electric actuator harness connector terminal 9 and ground.

Is the measured voltage within the specified range?

4.5-5.5V

Go to Step 3

Go to Step 5

3

Use a DMM to measure the voltage between the LH electric actuator harness connector terminal  7 and terminal 9.

Is the measured voltage within the specified range?

4.5-5.5V

Go to Step 4

Go to Step 6

4

Replace the LH electric actuator. Refer to Temperature Actuator Replacement (LH) .

Is the repair complete?

--

Go to Step 7

--

5
  1. Check for a poor connection or open in circuit 1218 (BRN/WHT). Refer to Testing for Intermittent Conditions and Poor Connections and Circuit Testing in Wiring Systems.
  2. Replace the heater-A/C control if circuit 1218 (BRN/WHT) is OK . Refer to Control Assembly Replacement .

Is the repair complete?

--

Go to Step 7

--

6
  1. Check for a poor connection or open in circuit 61 (YEL). Refer to Testing for Intermittent Conditions and Poor Connections and Circuit Testing in Wiring Systems.
  2. Replace the heater-A/C control if circuit 61 (YEL) is OK . Refer to Control Assembly Replacement .

Is the repair complete?

--

Go to Step 7

--

7

Operate the system to verify that it operates properly.

Does the system operate properly?

--

System OK

Go to Diagnostic System Check