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

1. Turn ON the ignition, with the engine OFF.
2. Add a load of 300 lbs to the rear of the vehicle.

Does the automatic level control air compressor operate?

Go to Step 3

Go to Step 4

Does the rear of the vehicle rise and not leak down?

Go to Automatic Level Control Sensor Adjustment

Go to Automatic Level Control System Leak Test

1. Disconnect the automatic level control sensor connector.
2. Connect a test lamp between the automatic level control sensor supply voltage circuit and a good ground.

Does the test lamp illuminate?

Go to Step 5

Go to Step 14

Connect a test lamp between the automatic level control sensor supply voltage circuit and the automatic level control sensor ground circuit.

Does the test lamp illuminate?

Go to Step 6

Go to Step 19

Connect a test lamp between the automatic level control relay control circuit and a good ground.

Does the test lamp illuminate?

Go to Step 7

Go to Step 8

Connect a 10 amp fused jumper wire between the automatic level control relay control circuit and a good ground.

Does the automatic level control compressor activate?

Go to Step 25

Go to Step 10

Test the automatic level control relay control circuit of the automatic level control relay connector with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 20

Go to Step 9

Test the accessory voltage circuit of the automatic level control relay connector with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 26

Go to Step 21

1. Leave the 10 amp fused jumper wire connected between the automatic level control relay control circuit and a good ground
2. Disconnect the automatic level control air compressor connector.
3. Connect a test lamp between the automatic level control compressor motor supply voltage circuit and a good ground.

Does the test lamp illuminate?

Go to Step 11

Go to Step 12

Connect a test lamp between the automatic level control compressor motor supply voltage circuit and the automatic level control compressor motor ground circuit.

Does the test lamp illuminate?

Go to Step 16

Go to Step 22

Test the automatic level control compressor motor supply voltage circuit of the automatic level control relay connector with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 23

Go to Step 13

Test the battery positive voltage circuit of the automatic level control relay connector with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 26

Go to Step 24

Test the automatic level control sensor supply voltage circuit of the automatic level control inflation time relay connector with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 17

Go to Step 15

Test the battery positive voltage circuit of the automatic level control inflation time relay connector with a test lamp connected to a good ground.

Does the test lamp illuminate?

Go to Step 27

Go to Step 18

Test the automatic level control compressor harness for a poor connection or an open. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs or Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 29

Go to Step 28

Repair the open in the automatic level control sensor supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

Repair the open in the battery positive voltage circuit to the automatic level control inflation time relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

Repair the open in the automatic level control sensor ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

Repair the open the automatic level control relay control circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

Repair the open in the accessory voltage circuit to the automatic level control relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

Repair the open in the automatic level control air compressor ground circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

Repair the open the automatic level control compressor motor supply voltage circuit. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

Repair the open in the battery positive voltage circuit to the automatic level control relay. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you complete the repair?

Go to Step 29

--

Replace the automatic level control sensor. Refer to Automatic Level Control Sensor Replacement .

Did you complete the replacement?

Go to Step 29

--

Replace the automatic level control relay.

Did you complete the replacement?

Go to Step 29

--

Replace the automatic level control inflation time relay.

Did you complete the replacement?

Go to Step 29

--

Replace the automatic level control air compressor. Refer to Air Compressor Replacement .

Did you complete the replacement?

Go to Step 29

--

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3