Air Suspension Height Sensor

This procedure addresses a replacement or diagnostic service for an air suspension height sensor on a 1972 Ford F-100, though this vehicle was not originally equipped with air suspension from the factory.

Warnings

Tools required

Parts

• Air suspension height sensor × 1 — Match to aftermarket air suspension system installed
• Electrical connector (if damaged) × 1 — Match to existing connector

Preparation

1. Park vehicle on level, solid surface and engage parking brake
2. Chock front wheels securely
3. Identify which height sensor requires service (front or rear axle)
4. Locate the height sensor mounting position on the frame rail and suspension component (typically control arm, axle housing, or trailing arm)
5. Disconnect negative battery terminal to prevent electrical faults during connector service
6. If sensor is at rear, raise rear of vehicle with floor jack at rear axle center
7. If sensor is at front, raise front of vehicle with floor jack at front crossmember
8. Place jack stands under frame rails at manufacturer-recommended lift points
9. Lower vehicle onto jack stands, leaving suspension hanging freely with no load

Procedure

1. 1

   Locate and inspect height sensor
   With suspension unloaded, locate the height sensor assembly. On most aftermarket air suspension systems, the sensor mounts to the frame rail with a bracket and connects via a linkage arm to the axle or suspension component. Inspect the sensor body, mounting bracket, linkage arm, and electrical connector for obvious damage, corrosion, or loose connections. Note the current position of the sensor linkage arm relative to the sensor body for reference during reinstallation.
2. 2

   Disconnect electrical connector
   Locate the electrical connector at the height sensor. Most aftermarket sensors use a 2-pin or 3-pin weatherpack-style connector. Press the locking tab on the connector housing and pull the connector halves apart. Inspect connector pins for corrosion or damage. If connector is corroded, spray with electrical contact cleaner and allow to dry.
3. 3

   Disconnect sensor linkage arm
   The linkage arm typically connects the sensor to the axle or control arm via a ball-and-socket joint or rod end. Remove the retaining clip (e-clip or cotter pin) securing the linkage arm to the axle-side mounting point. Use a flathead screwdriver to carefully pry the linkage arm ball joint from its socket if necessary. Note the orientation and position for reassembly.
4. 4

   Remove sensor mounting fasteners
   Remove the 2-3 mounting bolts securing the height sensor bracket to the frame rail. These are typically 5/16" or 3/8" bolts. Support the sensor as you remove the final fastener to prevent it from falling. Remove the sensor assembly from the vehicle.
5. 5

   Clean mounting location
   Use a wire brush to clean the sensor mounting location on the frame rail, removing rust, dirt, and old thread-locking compound. Clean the axle-side linkage mounting point as well. This ensures proper sensor alignment during reinstallation.
6. 6

   Install new height sensor
   Position the new height sensor bracket to the frame rail mounting location, aligning the mounting holes. Install the 2-3 mounting bolts finger-tight. Do not fully tighten yet, as sensor position may need adjustment during linkage connection.
7. 7

   Connect sensor linkage arm
   Extend or retract the sensor linkage arm to align with the axle-side mounting point. The linkage should be at approximately mid-travel when the suspension is at normal ride height. Connect the linkage arm ball joint to the axle-side socket and install the retaining clip (e-clip or cotter pin). Ensure the clip is fully seated and secure.
8. 8

   Adjust sensor position and tighten mounting bolts
   With the linkage connected, verify the sensor linkage arm is positioned at approximately mid-travel (center of its range of motion). This allows the sensor to read both compression and extension from normal ride height. Adjust sensor bracket position on the frame rail if needed to achieve proper linkage angle (typically 5-15 degrees from vertical). Tighten the sensor mounting bolts securely. Consult the specific installed air suspension system's documentation for the correct mounting bolt torque specification.
9. 9

   Reconnect electrical connector
   Reconnect the electrical connector to the height sensor, ensuring it clicks into place and the locking tab engages. Gently tug on the connector to verify it is secure. Route the wiring harness away from moving suspension components and exhaust, securing with zip ties if necessary.
10. 10

    Verify sensor mechanical operation
    Before lowering the vehicle, manually move the suspension through its range of travel by hand (pushing up on the axle). Observe the sensor linkage arm moving smoothly through its full range without binding or interference. The linkage should not reach the end of its travel at full suspension compression or extension.

Reassembly

1. Reconnect negative battery terminal
2. Raise vehicle slightly with floor jack to remove jack stands
3. Lower vehicle to ground slowly, allowing suspension to settle to normal ride height
4. Do not drive vehicle until sensor calibration and system verification is complete

Verification

• With vehicle at normal ride height and ignition on, verify the air suspension compressor does not cycle continuously, indicating sensor is reading properly
• If equipped with air suspension controller display, verify height sensor readings are within normal range (typically 2-3 volts at ride height for potentiometer-style sensors)
• Use multimeter to check sensor signal voltage if available (consult aftermarket system documentation for expected voltage range)
• Test drive vehicle and verify suspension maintains proper ride height during normal driving conditions
• Check for diagnostic trouble codes related to height sensor if air suspension system has diagnostic capability
• Verify no air leaks are present at airbag connections after suspension cycling

More procedures for this vehicle