For 1990-2009 cars
HVAC Components
Cell 68: Vacuum Tank - Pontiac
Cell 68: Passenger Air Mix Actuator (Buick)
Handling ESD Sensitive Parts Notice
Handling ESD Sensitive Parts Notice

### Circuit Description

The HVAC programmer commands the actuator to move by suppling battery voltage. The feedback supplied to the HVAC programmer is a regulated 5 volts. The feedback voltage is a function of the motor position with a high voltage of 4-5 volts indicating full cold door position. A low voltage of less than 1 volt indicates the full hot position. Operation of the air mix door actuator can be evaluated through the Scan Tool .

### Conditions for Setting the DTC

The ignition is ON.

### Action Taken When the DTC Sets

Only the full hot or full cold may be used by the system.

### Conditions for Clearing the DTC

• | Using a Scan Tool

• | A history DTC will clear when 40 consecutive IGN cycles have occurred without a malfunction.

• | HVAC programmer battery voltage is interrupted.

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 |

1. Turn the ignition switch to the RUN position.
2. Set the Scan Tool in order to "HVAC TESTS"--Data Pair for Mix Door #1.
3. Set the temperature to full cold.

Does the Scan Tool show a commanded (COM) mix door position that matches the specified value?

100%

Go to Step 2

Go to Step 6

2 | Set the temperature to full hot. Does the Scan Tool show a commanded (COM) mix door position hat matches the specified value? | 0% | Go to Step 3 | Go to Step 6
3 | Compare the actual (ACT value shown on the Scan Tool ), values both hot and cold with the commanded (COM). Are the values within the specified range? | 0-5% | Go to Step 6 | Go to Step 4
4 | Inspect the driver air mix valve for the following conditions:

• | Binding

• | Broken components

• | Improper adjustment

Are any of these conditions present?

--

Go to Step 5

Go to Step 6

5 | Repair the condition. Is the repair complete? | -- | System OK | --
6 | Replace the HVAC programmer. Refer to Programmer Replacement . Is the repair complete? | -- | System OK | --