Question about 1998 Cadillac DeVille

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Where is the leveling switch for the air suspension switch if there is one ?? where is it located at ??

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The sensors are located on the air springs themselves, and are adjustable (within reason) by moving them up or down in relation to their mounts.

Posted on Mar 24, 2011

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Ride height specification for 2002 Bravada and procedure on replacing sensors.Or where can I look on line for this information.


Air Suspension ??????

Air Suspension Description and Operation
Air Suspension
The primary mission of the Air Suspension System is the following for the rear suspension under loaded and unloaded conditions:
• Keep the vehicle visually level
• Provide optimal headlight aiming
• Maintain optimal ride height
The Air Suspension System consists of the following items:
• Air suspension compressor assembly
• Air suspension sensors
• Rear air springs
Important: The Air Suspension System must have a voltage supply of at least 12.6V to operate properly.
The Air Suspension System will maintain the rear D height within 4 mm (0.15 in) in all loading conditions and the leveling function will deactivate if the vehicle is overloaded. The side to side D height variation is maintained within 8 mm (0.31 in). After ignition is turned off, the air suspension control module (ASCM) will remain active for between 30 minutes and 2 1/2 hours. The system will exhaust pressure within 30 minutes after the ignition is turned off to lower the vehicle after unloading. In a temperature-controlled environment, the leakage of the complete load leveling system will not result in more than 1.4 mm (0.05 in) drop of rear suspension height at GVWR during a 24 hour period. If the outdoor temperature drops from +20°C (+68°F) to -5°C (+23°F), the rear D height may drop as much as 25 mm (1 in). However, the Air Suspension System should return to the specified D height when the ignition is again cycled to ON.

What is the problem ?

Diagnostic Trouble Code (DTC) Displaying
The Air Suspension system has an internal clock to prevent overheating if the compressor assembly is running for a prolonged period of time. If the system overheats, all leveling function stops until the system cools down. During this time, the indicator LED on the air inflator switch will be quickly flashing at a constant rate.
The other three diagnostic trouble codes are displayed with a blink code on the inflator switch LED. The Air Suspension Compressor Assembly shall begin to indicate the code when the condition to cause the code becomes current.
The number of the fault code shall be represented by the number of flashing pulses on the inflator switch LED. The flashing pulses shall have a repetition rate of 0.5 seconds and each code shall be separated by a 3.0 second delay. All codes shall be flashed in the order of occurrence of the fault. The blink code shall take priority over other processes that have access to the inflator switch LED. Refer to the following:
• DTC 001
• DTC 002
• DTC 003

Trim Height Uneven or Low ??????

Feb 24, 2017 | Cars & Trucks

1 Answer

Where exactly is the switch for the air suspension compressor on a 2006 Buick Lucerne CXL?


The automatic level control (ALC) system maintains a desired rear suspension position under all types of towing, hauling, and loading conditions.
The system uses the electronic suspension control module (ESCM), ALC relay, ALC compressor assembly, air dryer, air lines, LR and RR shock absorbers with integral air chambers, LR and RR suspension position sensors, exhaust valve, driver information center (DIC), and the serial data circuit to perform the system functions.
What switch ? there are sensors at the wheels that control the system .
The system uses the automatic level control module (ALCM) with integral suspension position sensor, ALC relay, ALC compressor assembly, air dryer, air lines, LR and RR shock absorbers with integral air chambers, exhaust valve, driver information center (DIC), and the serial data circuit to perform the system functions.

The

Jul 10, 2016 | Buick Cars & Trucks

2 Answers

Function of suspension switch


AIR COMPRESSOR TO AIR RIDE IS POWERED DOWN.

Jan 22, 2014 | 1993 Lincoln Mark VIII

2 Answers

2000 navigator: sit higher on one side than the other.


the air ride suspension has level sensors under the vehicle, one of the sensors must be bad making the truck deflate the airbag or inflate it too much. you may need to have someone with a scan tool to access the air suspension module and check for fault codes. you can try turning the air suspension switch off for about an hour to see if the system will reset. the switch is located under the dash on the right side kick panel.

Aug 03, 2011 | 2000 Lincoln Navigator

1 Answer

2001 ford expidition, back end low and ck susp. light came on


at a guess you need new valves or air bags for the suspension. not cheap & best left to professionals. whenever you have to jack or tow vehicle to a point where the vehicle is out of level, make sure to disable the air suspension using the switch located near the front seat passenger's feet up under dash, in a corner. this helps prevent damage to air bag system & repairs

Oct 15, 2009 | 2001 Ford Expedition

3 Answers

The rear suspension air bags no work


start here

The air suspension system is designed to improve ride, handling and general vehicle performance for static, on-road and off-road driving condition:
  • 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, 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 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) transfer case inputs, 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 an air spring with an air spring solenoid.
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 and the vehicle speed exceeds 16 km/h (10 mph).
Air Suspension Switch
The air suspension switch is located behind the RH kick panel on a mounting bracket. The switch interrupts power to the air suspension control module.
The air suspension switch supplies a signal to the air suspension control module. Without the air suspension control module receiving this signal the load leveling system is inoperative and will not react when rear of the vehicle is raised or lowered. If the air suspension system is disabled by turning off air suspension switch, a "CHECK SUSP" will appear in the RH corner of the instrument cluster with the ignition in the run position.
Air Compressor
The RAS air compressor:
  • Is not interchangeable with four wheel air suspension (4WAS) compressor.
  • Consists of the compressor and vent solenoid; neither are replaceable as individual items.
  • Is mounted in the engine compartment between the washer fluid bottle and headlamp (RH front corner).
  • Is a single cylinder electric motor driven unit that provides pressurized air as required.
  • Is powered by a solid state relay, controlled by the air suspension control module.
  • Passes pressurized air through the compressor air drier that contains silica gel (a drying agent). Moisture is then removed from the compressor air drier when vented air passes out of the system during vent operation.
  • Air drier has a single port and is not interchangeable with 4WAS compressor air drier.
  • Air drier may be replaced separately.
  • Incorporates a snorkle that may be replaced separately.
The vent solenoid:
  • Allows air to escape from the system during venting actions.
  • Is located in the air compressor cylinder head.
  • Has a 160 psi internal relief valve.
  • Shares a common electrical connector with the air compressor motor.
  • Is enclosed in the cylinder head casting, which forms an integral valve housing that allows the valve tip to enter the pressurized side of the system.
  • Has an O-ring seal that prevents air leakage past the valve tip.
  • Opens when the air suspension control module determines lowering is required.
  • Provides an escape route for pressurized air that opens when system pressures exceed safe operating levels.
  • Is replaced with the air compressor as a unit.
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 air springs are mounted between the axle spring seats and the frame upper spring seats.
The two air springs replace the conventional rear coil springs.
Air Suspension Height Sensor
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.
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 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 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). Replace the air suspension height sensor as a unit.
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 of the vehicle and related components.
The air suspension control module is mounted in the passenger compartment inside the instrument panel above the radio and temperature controls.
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.
Air Suspension Diagnostic Connector
The air suspension diagnostic connector is used to aid the technician in diagnosing the air suspension system. It is also used to vent the system of compressed air when air suspension system components need to be repaired or replaced. The air suspension diagnostic connector is located under steering column.

Oct 02, 2009 | 1998 Ford Expedition

1 Answer

2002 linncoln towncar where is the air supension compressor relay switch,please.


Air suspension needs compressed air for the control of Air Springs (Air Spring is a cylinder like thing which goes up and down when air is pumped in and out of it). For pumping in and out the air, air compressor needs to be switched ON/OFF. Compressor relay connects and disconnects the compressor motor from the power supply ( battery). ----------------- air ride suspension compressor located under the air filter box . ---------------- the Air compressor clutch relay location
is fitted to the left hand inner wing (when viewed from the the driving seat).
-------------------
the compresser is located on the left hand side of the car under the hood.
once you open the hood remove the air cleaner housing and windshield washer resivor.
there is a panel that you lift up under both of thoese that is where the compresser is located
-------------
  1. The air suspension uses a small, separate air compressor under the driver's side left fenderwell, with air lines running to the air bags. On the top of each air bag is a electrical valve. This is a relief valve that allows air to be exhausted when activated, and which senses the amount of air pressure within the air bag to keep both sides equal. These valves are operated via a leveling sensor that is attached to the body of the car and to the rear axle by a movable arm. When the rear of the car drops due to increased load, the arm is pushed up. When the arm is pushed up, it turns on the air compressor and fills the air bags to level the car. When the load is removed and the arm moves down, indicating that the back of the car has risen, the sensor opens the valve on the air bags and allows air to escape, lowering the car.
  2. If the back of the car is low, indicating that the air suspension is not working, and the air suspension light is on, check the fuse first. If the fuse is all right, check the air suspension switch in the trunk and make sure it is on. This switch is used when the car is in for service. Always turn off the switch before lifting the car, because the sensor will think the car is rising and keep the air bag valves open, ruining the rear air suspension.
  3. Turn the ignition key with the engine off. Listen for the compressor to come on while pushing down on the rear bumper. If it does not come on, test the switch terminals for power, using a circuit tester. If one terminal has power and the other does not, replace the switch. If there is power, turn the switch to the off position, raise the vehicle and place it on jack stands in the rear. Inspect the leveling switch on the axle, making sure it is not bent and is connected. Use an ohmmeter for this test. Pull the electrical connector off the switch. Loosen the arm of the switch from the axle. Test the switch with the ohmmeter by checking across both terminals while slowly moving the arm. There should be no continuity with the arm down. As the arm is raised, there should be continuity. If not, replace the switch. If there was continuity, connect the arm and the electrical connector.
  4. Put a floor jack under the axle and raise the axle to the point where it is just beginning to lift the car off the jack stand. Turn on the ignition. Turn the air suspension switch to the "on" position. Use the circuit tester to check for power at the leveling switch. If there is power, turn the air suspension switch to "off" and lower the car. Access the air compressor in the front, under the hood, and check the electrical connector for power. If there is power, check for a good ground. If both are good, replace the compressor. If the compressor works and the car does not rise in the back, replace the air bags.


Sep 11, 2009 | 2002 Lincoln Town Car

2 Answers

Can any one tell me were how i can find the automatic level control on my 1994 town car


Description and Operation The rear air suspension:
  • Is an air-operated, microprocessor-controlled, suspension system.
  • Replaces the conventional rear coil spring suspension.
  • Provides low spring rates for improved ride and automatic rear load leveling.
  • Is standard equipment on the Town Car.
  • Is available as optional equipment on Crown Victoria and Grand Marquis.
The rear air suspension system has the following features:
  • The system is operational with the ignition switch in the RUN position.
  • Automatic rear load leveling has limited operation for one hour after ignition switch is turned to OFF.
  • The air suspension switch, located on the right side of the luggage compartment, must be turned OFF when the vehicle is on a hoist, being towed or jump started.
  • The Air Suspension warning indicator is located in the instrument panel, to the right of the speedometer.
    • The warning indicator flashes five times and then stays on when service switch is turned off or a system malfunction is detected.
  • The rear leveling system operates by adding or removing air in the springs to maintain the level of the vehicle at a predetermined rear suspension D ride height dimension, and is controlled by a control module (5A919) .
  • The rear air suspension control module also controls the electronic variable orifice (EVO) steering.
  • Refer to Section 11-02 for Description of the EVO steering system.
  • Air required for leveling the vehicle is distributed from the air compressor to the rear air springs by a nylon air line which runs from the compressor air dryer (5346) through a Y-fitting to each individual air spring.


Suspension, Computer Controlled—Town Car

c441c13.gif
Item Part Number Description 1 9C392 Compressor Relay Power Junction Block 2 5A897 Air Line (Attached to Brake/Fuel Bundle) 3 5319 Air Compressor With Regenerative Air Dryer and Vent Solenoid 4 5A897 Air Line to Compressor 5 5K761 Air Suspension Service Switch 6 14489 Data Link Connector 7 — Quick Connect 8 — To LH Air Spring 9 — From Compressor 10 — Y-Fitting (Part of 5A911) 11 — To RH Air Spring 12 5A908 Heat Shield 13 5A966 Spring Retainer Clip 14 5560 Rear Spring 15 5359 RearAir Suspension Height Sensor 16 5A919 Control Module 17 14018 Air Spring Solenoid

Control Module Power and Ground The control module (5A919) has the following features:
  • Power is provided by Circuit 418 and is controlled by the air suspension switch.
    • The air suspension switch is powered through a 15 amp fuse in Circuit 296 in Town Car.
    • AIR SUSPN PUMP (30A MAXI) fuse provides this power through Circuit 414 in the Crown Victoria/Grand Marquis.
  • Control module ground is provided through control module wire harness Pins 6 and 21, to the RH inner quarter panel sheet metal, near the control module .
---------------------------------
Weight Added When weight is added to the vehicle:
  • The air suspension height sensor (5359) length is reduced from trim length, sending a "rear is low" signal to the control module (5A919).
  • The control module then turns the compressor on by grounding the compressor relay control Circuit 420. This restores the rear of the vehicle to trim position.
    • Battery voltage is provided to the relay coil by Circuit 414.
  • The control module opens the spring solenoid valves (5311) by switching Circuits 416 and 429 to ground. This allows pressurized air to enter the springs.
    • Battery voltage is provided to the air spring solenoid valves by Circuit 414.
  • Compressed air flows from the compressor, through the compressor air dryer (5346) airlines and spring solenoid valves into the rear springs (5560).
  • As the rear springs raise the rear body height, the air suspension height sensor increases in length until the preset trim height is reached.
  • The control module then turns off the compressor (through the relay) and closes the air spring solenoid valves.
----------------------------------------------------------------------
Weight Removed When weight is removed:
  • The air suspension height sensor (5359) length is increased from the trim length, sending a "rear is high" signal to the control module (5A919).
  • The control module then opens the vent solenoid valve (located in the compressor assembly) by switching Circuit 421 to ground and opens the solenoid valves (5311) by switching Circuits 416 and 429 to ground. This restores the rear of the vehicle to trim position.
  • Compressed air flows from rear springs (5560), through the air spring solenoid valves, air lines, compressor air dryer (5346), and out the vent solenoid valve.
  • As the body lowers, the air suspension height sensor length decreases until the preset trim height is reached.
  • The control module then closes the vent and solenoid valves.
-----------------------------------------
Control module operates as follows:
  • In general the control module uses a 45-second averaging interval to determine when compress and vent operations are needed.
  • However, door courtesy lamp switch (13713) inputs can override the 45-second averaging interval so compress and vent operations can begin immediately, if needed.
  • The 45-second averaging interval is used to keep the control module from making unneeded corrections.
  • When a vehicle at the correct rear trim height hits a bump, the air suspension height sensor output will read low and high in addition to trim until the oscillations die out.
  • If the control module were to correct for these "bump induced readings", system duty cycle would increase unnecessarily.
  • The 45-second averaging interval not only eliminates corrections due to bumps, but also eliminates unneeded corrections resulting from braking, accelerating, and turning. The control module tabulates the air suspension height sensor readings, and does not begin a compress or vent operation until the air suspension height sensor (5359) reads low or high for 45 seconds consistently.
  • There are more restrictions on vent operations than there are on compress operations.
  • To eliminate the chance of catching a door on a curb as the vehicle vents down, the control module will not allow any venting to occur when a door is open.
  • The control module does not allow any vent operations for the first 45 seconds after the ignition switch (11572) has been turned to RUN.
    • Even if a vehicle is extremely high in the rear, DO NOT expect it to vent until the ignition switch has been turned to RUN for 45 seconds.

Jun 24, 2009 | 1994 Lincoln Town Car

3 Answers

Rear air bag suspension failure 1998 Ford EXP E.B. 2x2


this will get you started. report back on progress and we'll go from there. There is a diagnostic test that will provide codes I think. I will look.

The system consists of unique rear air springs, 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 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) transfer case inputs, 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 an air spring with an air spring solenoid.
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 and the vehicle speed exceeds 16 km/h (10 mph).
Air Suspension Switch
The air suspension switch is located behind the RH kick panel on a mounting bracket. The switch interrupts power to the air suspension control module.
The air suspension switch supplies a signal to the air suspension control module. Without the air suspension control module receiving this signal the load leveling system is inoperative and will not react when rear of the vehicle is raised or lowered. If the air suspension system is disabled by turning off air suspension switch, a "CHECK SUSP" will appear in the RH corner of the instrument cluster with the ignition in the run position.
Air Compressor
The RAS air compressor:
  • Is not interchangeable with four wheel air suspension (4WAS) compressor.
  • Consists of the compressor and vent solenoid; neither are replaceable as individual items.
  • Is mounted in the engine compartment between the washer fluid bottle and headlamp (RH front corner).
  • Is a single cylinder electric motor driven unit that provides pressurized air as required.
  • Is powered by a solid state relay, controlled by the air suspension control module.
  • Passes pressurized air through the compressor air drier that contains silica gel (a drying agent). Moisture is then removed from the compressor air drier when vented air passes out of the system during vent operation.
  • Air drier has a single port and is not interchangeable with 4WAS compressor air drier.
  • Air drier may be replaced separately.
  • Incorporates a snorkle that may be replaced separately.
The vent solenoid:
  • Allows air to escape from the system during venting actions.
  • Is located in the air compressor cylinder head.
  • Has a 160 psi internal relief valve.
  • Shares a common electrical connector with the air compressor motor.
  • Is enclosed in the cylinder head casting, which forms an integral valve housing that allows the valve tip to enter the pressurized side of the system.
  • Has an O-ring seal that prevents air leakage past the valve tip.
  • Opens when the air suspension control module determines lowering is required.
  • Provides an escape route for pressurized air that opens when system pressures exceed safe operating levels.
  • Is replaced with the air compressor as a unit.
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 air springs are mounted between the axle spring seats and the frame upper spring seats.
The two air springs replace the conventional rear coil springs.
Air Suspension Height Sensor
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.
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 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 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). Replace the air suspension height sensor as a unit.
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 of the vehicle and related components.
The air suspension control module is mounted in the passenger compartment inside the instrument panel above the radio and temperature controls.
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.
Solenoid Valve, Air Spring
swj~us~en~file=ani_caut.gif~gen~ref.gif WARNING: Never rotate an air spring solenoid valve to the release slot in the end cap fitting until all pressurized air has escaped from the spring to prevent damage or injury.
The air spring solenoid:
  • allows air to enter and exit the air spring during leveling operations.
  • is electrically operated and controlled by the air suspension control module.
Air Suspension Diagnostic Connector
The air suspension diagnostic connector is used to aid the technician in diagnosing the air suspension system. It is also used to vent the system of compressed air when air suspension system components need to be repaired or replaced. The air suspension diagnostic connector is located under steering column.

Jun 01, 2009 | 1998 Ford Expedition

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