GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Automatic Level Control Schematics

1

Did you perform the Automatic Level Control Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Automatic Level Control

2

Is the rear of the vehicle too high?

Go to Step 3

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

3

Disconnect the air tube from the compressor.

Does the rear of the vehicle drop?

Go to Step  4

Go to Step  6

4

Disconnect the compressor motor relay.

Does the compressor motor continue to run?

Go to Step  5

Go to Step  7

5

Test the battery positive voltage circuit of the compressor motor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step  8

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6

Inspect all air tubes for kinked, bent and blockage. Check the exhaust valve for blockage.

Did you find and correct the condition?

Go to Step  8

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7

Replace the compressor motor relay.

Did you complete the replacement?

Go to Step  8

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8

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3