For 1990-2009 cars

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Suspension Controls Schematics
1 | Did you review the air suspension description and operation and perform the necessary inspections? | Go to Step 2 | Go to Air Suspension Description and Operation
2 | Verify the fault is present. Does the system operate normally? | Go to Testing for Electrical Intermittents in Wiring Systems | Go to Step 3
3 |

1. Disconnect the air suspension relief valve.
2. Ensure the air suspension dump switch is in the ON position.
3. Connect a test lamp between the control circuit of the air suspension relief valve and the ground circuit of the air suspension relief valve. Refer to Circuit Testing in Wiring Systems.
4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 7

Go to Step 4

4 |

1. Turn OFF the ignition.
2. Connect a test lamp between the control circuit of the air suspension relief valve and a good ground. Refer to Circuit Testing in Wiring Systems.
3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 10

Go to Step 5

5 |

1. Turn OFF the ignition.
2. Gain access to back of the air suspension dump switch.
3. Connect a test lamp, and back probe between the ignition voltage circuit and a good ground. Refer to Circuit Testing in Wiring Systems.
4. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 6

Go to Step 8

6 |

1. Turn OFF the ignition.
2. Connect a test lamp, and back probe between the air suspension relief valve solenoid control circuit and a good ground. Refer to Circuit Testing in Wiring Systems.
3. Turn ON the ignition, with the engine OFF.

Does the test lamp illuminate?

Go to Step 9

Go to Step 12

7 | Inspect for poor connections at the harness connector of the air suspension relief valve. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | Go to Step 11
8 | Check the air suspension dump switch ignition circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | --
9 | Check the air suspension relief valve control circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | --
10 | Check the air suspension relief valve ground circuit for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | Go to Step 13 | --
11 | Replace the air suspension relief valve. Refer to Air Suspension Relief Valve Replacement . Did you complete the replacement? | Go to Step 13 | --
12 | Replace the air suspension dump switch. Did you complete the replacement? | Go to Step 13 | --
13 | Operate the system in order to verify the repair. Did you correct the condition? | System OK | Go to Step 3