For 1990-2009 cars

Step | Action | Value(s) | Yes | No
--- | --- | --- | --- | ---
1 | Did you perform the ALC System Check? | --- | Go to Step 2 | Go to Automatic Level Control System Operation Check
2 | Check the ELC/TRAILER Fuse. Is the ELC/TRAILER Fuse open? | -- | Go to Step 3 | Go to Step 4
3 | Repair the short to ground in CKT 1240. Has the repair been made and the system rechecked? | -- | System OK | --
4 | Check the PWR QTR VENT Fuse. Is the PWR QTR VENT Fuse open? | -- | Go to Step 5 | Go to Step 6
5 | Repair the short to ground in CKT 743. Has the repair been made and the system rechecked? | -- | System OK | --
6 |

1. Disconnect the auto level control air compressor connector.
2. Using a J 39200 , measure the voltage between the auto level control air compressor connector terminals C and E to ground.

Is the voltage within the specified range?

9 - 14 V

Go to Step 7

Go to Step 8

7 |

1. Turn the ignition switch to the ON position.
2. Using a J 39200 , measure the voltage between the auto level control air compressor connector terminal A and ground.

Is the voltage within the specified range?

9 - 14 V

Go to Step 9

Go to Step 10

8 | Repair the poor connection or open in CKT 1240, between the auto level control air compressor connector terminals C and/or E and S445. Has the repair been made and the system rechecked? | -- | System OK | --
9 | With the ignition switch still in the ON position, measure the voltage between the auto level control air compressor connector terminals A and G. Is the voltage within the specified range? | 9 - 14 V | Go to Step 11 | Go to Step 12
10 | Repair the poor connection or open in CKT 1725, between the auto level control auto compressor connector terminal G and G401. Has the repair been made and the system rechecked? | -- | System OK | --
11 |

1. Set the ignition switch to the OFF position.
2. Disconnect the auto level control air inflator relay connector.
3. Using a J 39200 , measure the voltage between the auto level control air inflator relay connector terminal D and ground.

Is the voltage within the specified range?

9 - 14 V

Go to Step 13

Go to Step 14

12 | Repair the poor connection or open in CKT 743, between the auto level control air compressor connector terminal A and S465. Has the repair been made and the system rechecked? | -- | System OK | --
13 | Using a J 39200 , measure the voltage between the auto level control air inflator relay connector terminals D and H. Is the voltage within specified range? | 9 - 14 V | Go to Step 15 | Go to Step 16
14 | Repair the poor connection or open in CKT 1240, between the auto level control air inflator relay connector terminal D and S445. Has the repair been made and the system rechecked? | -- | System OK | --
15 |

1. Disconnect the auto level control sensor connector.
2. Connect a 10 A fused jumper wire between the auto level control air compressor connector terminals E and D.
3. Using a J 39200 , measure the voltage at the auto level control air inflator relay connector terminal E and at the auto level control sensor connector terminal B.

Is the voltage within the specified range?

9 - 14 V

Go to Step 17

Go to Step 18

16 | Repair the poor connection or open in CKT 321, between the auto level control air inflator relay connector terminal E, the auto level control sensor connector terminal B, and the auto level control air compressor connector terminal D. Has the repair been made and the system rechecked? | -- | System OK | --
17 |

1. Remove the jumper wire from the auto level control air compressor connector terminals E and D and install it between the auto level control air inflator relay connector terminals D and B.
2. Using a J 39200 , measure the voltage between the auto level control sensor connector terminal C and ground.

Is the voltage within the specified range?

9 - 14 V

Go to Step 19

Go to Step 20

18 | Repair the poor connection or open in CKT 321, between the auto level control air inflator relay connector terminal E, the auto level control sensor connector terminal B, and the auto level control air compressor connector terminal D. Has the repair been made and the system rechecked? | -- | System OK | --
19 |

1. Reconnect the auto level control air compressor, the auto level control air inflator relay, and the auto level control sensor connectors.
2. Disconnect the air inflator switch connector.
3. Turn the ignition switch to the ON position.
4. Using a J 39200 , measure the voltage between the air inflator switch connector terminal A and ground.

Is the voltage within the specified range?

9 - 14 V

Go to Step 21

Go to Step 22

20 | Repair the poor connection or open in CKT 1248, between the auto level control air inflator relay connector terminal B the auto level control sensor connector terminal C. Has the repair been made and the system rechecked? | -- | System OK | --
21 |

1. Turn the ignition switch to the OFF position.
2. Connect a 10 A fused jumper wire between the air inflator switch connector terminals A and B.
3. Turn the ignition switch to the ON position.

Is the auto level control air compressor on?

--

Go to Step 23

Go to Step 24

22 |

1. Repair the poor connection or open in CKT 1245, between the air inflator switch terminal A and the auto level control air inflator relay connector terminal F.
2. If CKT 1245 is OK, replace the auto level control air inflator relay. Refer to Automatic Level Control Relay Replacement .

Has the repair been made and the system rechecked?

--

System OK

--

23 |

1. Turn the ignition switch to the OFF position.
2. Disconnect the auto level control air compressor relay.
3. Connect a 10 A fused jumper wire between terminals 1 and 4 of the air compressor relay connector.
4. Turn the ignition switch to the ON position.

Is the auto level control air compressor on?

--

Go to Step 25

Go to Step 26

24 |

1. Repair the poor connection or open in CKT 1725, between the air inflator switch terminal B and S441.
2. If OK, replace the air inflator switch. Refer to Automatic Level Control Inflator Air Switch Replacement .

Has the repair been made and the system rechecked?

--

System OK

--

25 | Replace the auto level control air compressor relay. Has the repair been made and the system rechecked? | -- | System OK | --
26 | Replace the auto level control air compressor. Refer to Air Compressor Replacement . Has the repair been made and the system rechecked? | -- | System OK | --