Rear Suspension 2002 Ford Expedition

Cheryl should of changed to standard suspension and gave up the air ride.

it is at the rear end and looks look a guide rail with a plug I would first try to clean the connector and apply carbon conductive grease/NOT LITHIUM==OR DIELECTRIC THERE THE WRONG STUFF/and see if it responds it's only been there for 161/2 years braving winter after winter and its either still good or done from a lack of attention needed taking it out and really cleaning just might save some$$$$$

Hi,
I have an alternate suggestion. I've had several Ford Products with those compressors in the. A 1990 and 1994 Continental with complete Air Suspension systems in the. And several Lincoln Town cars with air suspension systems for the rear wheels. Most of the time when these vehicles go to the grave yard, the compressors have out-lived them. I would go to the Junk yard and get one for a song and take to a local garage (not the dealer) and have it installed. You may even be able to do it yourself.
I have seen no variation in the design of the ones I've seen except for the air manifold. I would get one that was used in an Lincoln Town Car because it was used for leveling the rear suspension.
The air manifold in it would be very similar, if not identical, to your vehicle.
After all, The only thing an Air compressor "sees" is air.
I hope this suggestion is helpful to you.
Happy New Year,
Mark

i have 2000 ford expedition that dealer just replaced trailing arms now rear air suspension wont work now what or is there somethig to check first

sounds like possibly the bags are blown or either lines leaking if it's the bags blown out there are a couple choices replace the bags obviously or you can get an aftermarket kit to do away with the air ride suspension and put regular springs and shocks under it which is alot cheaper than new bags. but make sure you don't have a line that has ruptured

that very common on this model. I hope you have a service contract to cover this.

I had a 1999 Expedition. When you put the 4x4 on it raises the vehicle an extra inch or 2.
It may help to turn the 4x4 off. Two wheel drive is a lower air setting.
Your original pump may still be good. The problem can be in the front. The compressor is not filling the front suspension to the cutoff point. It will lift the rear after the front end is at running height. Since you lost the front end first, the remaining air bled out there and then the rear came down. Once you shut down the car the suspension was done, all the air was let go.
There are adjustment solenoids on the body but you need someone qualified to repair this.

is switch on?
The air suspension switch and bracket is mounted below the RH side of the instrument panel.

Dealer can run diagnostic test with scan tool for fault codes.
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The air suspension system is designed to improve ride, handling and general vehicle performance for static, on-road and off-road driving conditions:

• Ride is improved by using an air type spring (the soft ride is inherent).
• Handling is improved by maintaining constant vehicle attitude.

The system consists of unique rear air springs, the air compressor, air lines, air spring solenoids, height sensor, air suspension control module, attachments and associated signals derived from both driver and road inputs. With these components and signals, the air suspension control module commands changes in vehicle height that are necessary for the load leveling features.
The load leveling feature rear air suspension (RAS) systems shall automatically make adjustments in vehicle height so that the vehicle is always at trim height and constant front-to-rear vehicle attitudes are maintained over the expected load range of the vehicle. Adjustments in height that are necessary to correct height differences between the vehicle's left and right sides for the RAS system shall be restricted to what can be reliably achieved with one air suspension height sensor.
The system uses one air suspension height sensor, a steering sensor, generic electronic module (GEM) and other vehicle sensors to measure driver and road inputs. The system changes vehicle height using an air compressor, two air lines and the use of air springs with air spring solenoids.
The air suspension system holds vehicle height when the rear hatch or any door is opened. The system stores rear vehicle height the moment any open door is detected. The system then maintains this height regardless of the addition or removal of a load. The system will return to its commanded height when all doors are closed or the vehicle speed exceeds 16 km/h (10 mph).
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Air Spring
RAS vehicles use air springs in the rear. The air springs provide a varying spring rate proportional to the systems air pressure and volume. The air suspension system regulates the air pressure in each air spring by compressing and venting the system air. Increasing air pressure (compressing) raises the rear of the vehicle while decreasing air pressure (venting) lowers the rear of the vehicle. Vehicle height is maintained by the addition and removal of air in each air spring through an air spring solenoid installed in the upper spring cap and energized through the air suspension control module.
The two air springs support the conventional rear leaf coil springs.
Air Suspension Height Sensor
One air suspension height sensor is mounted on the vehicle. The air suspension height sensor sends a voltage signal to the air suspension control module. The output ranges from approximately 4.75 volts at minimum height (when the vehicle is low or in full jounce), to 0.25 volts at maximum height (when the vehicle is high or in full rebound). The air suspension height sensor has a useable range of 80 mm (3.2 in) compared to total suspension travel of 200-250 mm (8 to 10 in) at the wheel. Therefore, the air suspension height sensor is mounted to the suspension at a point where full rear suspension travel at the wheel is relative to 80 mm (3.2 in) of travel at the air suspension height sensor. The air suspension height sensor is attached between the No. 5 frame crossmember (upper socket) and the panhard rod (lower socket).
When the air suspension height sensor indicates that the rear of the vehicle is lower than trim under normal driving conditions, the air compressor will turn on and pump compressed air to the air springs. When the sensor indicates that the rear of the vehicle is raised above trim under normal driving conditions, this will cause the air to be vented from the air springs to lower the vehicle back to its trim height level.
Compressor Relay
The compressor relay is energized by the air suspension control module to allow high current to flow from the battery to the compressor motor.

• A solid state relay is used in the air suspension system for air compressor control. The relay incorporates a custom power metal oxide semi-conductor field effect transistor (MOSFET) and ceramic hybrid circuitry. The relay switches high current loads in response to low power signals and is controlled by the logic of the air suspension control module.

Air Suspension Control Module
NOTE: The 4WAS air suspension control module is used for the RAS system. The internal processor recognizes external circuitry to determine if it is installed in a 4WAS or a RAS equipped vehicle.
NOTE: The air suspension control module is calibrated with information from the air suspension height sensor. A new or exchanged air suspension control module requires a ride height adjustment calibration process to be performed.
The air suspension control module controls the air compressor motor (through a solid state relay), and the air spring solenoids. The air suspension control module also provides power to the air suspension height sensor. The air suspension control module controls vehicle height adjustments by monitoring the air suspension height sensor, vehicle speed, a steering sensor, acceleration input, the door ajar signal, transfer case signals, and the brake pedal position (BPP) switch. The air suspension control module also conducts all fail-safe and diagnostic strategies and contains self-test and communication software for testing the vehicle and related components.
The air suspension control module monitors and controls the air suspension system through a 32-pin two-way connector. The air suspension control module is keyed so that the air suspension control module cannot be plugged into an incorrect harness. There are two sides of the harness connection to the air suspension control module. Each is uniquely colored and keyed to prevent reversing the connections.
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Visual Inspection Chart Mechanical Electrical

• Restricted suspension movement
• Excessive vehicle load
• Cut, severed or crimped air line(s)
• Unmounted height sensor
• Damaged air spring(s)

• Open fuses:
  • Central junction box (CJB) Fuse 4 (15A), 6 (5A) and 20 (5A)
  • Battery junction box (BJB) Fuse 109 (50A)
• Loose, corroded or disconnected connectors
• Air suspension switch is in the OFF position
• Damaged solenoid valve(s)

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• The compressor is inoperative

• BJB Fuse 109 (50A).
• Air compressor assembly.
• Circuitry.
• Air suspension relay.

Try jacking up the vehicle and putting it on jack stands letting the suspension hang down. Disconnect the battery for a few minuts and reconnect it and it should inflate the airbags and level off the suspension.

There are ride height sensors in the rear that send a signal to the ride height/load leveling control module, one of these ,may be defective. Have Ford dealer run an active test of the system, they will find out what the part is that has failed, otherwise you are guessing, that equals wasted $$$