GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

1

Did you review the Automatic Level Control System Description and Operation and perform the necessary inspections?

Go to Step 2

Go to Symptoms - Automatic Level Control

2

  1. Turn ON the ignition, with the engine OFF.
  2. Turn ON the air inflator switch.
  3. Turn OFF the air inflator switch.

Does the ALC air compressor operate normally?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

  1. Disconnect the ALC air inflator relay connector.
  2. Connect a test lamp between the battery positive voltage circuit and the ALC reset signal circuit of the ALC air inflator relay connector.
  3. Press the air inflator switch OFF button.

Did the test lamp illuminate?

Go to Step 6

Go to Step 4

4

Test the ALC reset signal circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

System OK

Go to Step 5

5

Replace the ALC air inflator relay. Refer to Automatic Level Control Relay Replacement .

Did you complete the replacement?

Go to Step 7

--

6

Replace the ALC air inflator switch. Refer to Automatic Level Control Inflator Air Switch Replacement .

Did you complete the replacement?

Go to Step 7

--

7

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3