Warning: A sudden release of pressure may cause personal injury or damage to the vehicle. The air suspension is under pressure until the air supply lines are disconnected.

Note: Use the following precautions when servicing the air suspension system:

1. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
2. Remove the rear wheels. Refer to Tire and Wheel Removal and Installation.
3. Lower the vehicle with the rear axle supported by jackstands.



4. Raise or lower the vehicle until the D-height measurement is 25 mm (1 in) above the published D-height specification, 135 mm (5.33 in) for Trailblazer SS or 160 mm (6.33 in) for all other vehicles.
5. Turn the ignition key to the ON position. This will partially deflate the air spring.
6. After two minutes, turn the ignition key to the OFF position and remove the air suspension fuse. Refer to Electrical Center Identification Views.




Note: A D-height gage block (1) can be used to determine the D-height position. Create a D-height gage block using metal stock cut to 20 mm X 30 mm X the published D-height specification 110 mm (4.33 in) for Trailblazer SS and 135 mm (5.33 in) for all other vehicles. Use the block (1) as a measuring device only.

7. Raise or lower the vehicle so that the D-height is at published specification 110 mm (4.33 in) for Trailblazer SS or 135 mm (5.33 in) for all other vehicles.



8. Disconnect the air spring level sensor link from the upper control arm.



9. Disconnect the air spring level sensor electrical connector.



10. Remove the air spring level sensor-to-frame mounting bolts.
11. Remove the air spring level sensor from the vehicle.

1. Install the air spring level sensor link to the upper control arm.




Note: If not equipped, use a NEW anti-rotation bolt P/N 11569736.

2. Loosely install sensor mounting bolts with the anti-rotation bolt in the right hand mounting hole.

Caution: Refer to Fastener Caution in the Preface section.

Note: Do not remove the air spring level sensor locating pin until the air spring level sensor has been properly mounted and aligned.

3. While holding the body of the sensor, tighten the anti-rotation bolt first.

Tighten
Tighten the air spring level sensor frame mounting bolts to 8 N·m (71 lb in).




4. Connect the air spring level sensor electrical connector.



5. Verify the pin can be removed and installed with ease to ensure the correct sensor installation.

If the pin cannot be inserted with ease, loosen the sensor fasteners, adjust the sensor, and retighten the sensor fasteners so that the pin can be removed and installed with ease.

Caution: Failure to remove the air suspension auto level control sensor locating pin will cause damage to the air suspension auto level control sensor.

6. Remove the air spring level sensor locating pin.
7. Raise the vehicle off the jackstands and remove the jaskstands from under the vehicle.
8. Install the rear wheels. Refer to Tire and Wheel Removal and Installation.
9. Lower the vehicle.
10. Install the air suspension fuse.
11. Turn the ignition key to the ON position to inflate the rear air springs.
12. After two minutes, turn the ignition key to the OFF position.
13. Recycle the ignition, if needed.
14. Verify and record the D-height. Refer to Trim Height Specifications.