Air ride compressor runs when i shut off engine car is level no change in height when running just runs all the time had to unplug it to get it to quit but ride is still ok does this mean that the compressor is bad or??? 1993 buick park avenue

When you turn the key on, after a couple of seconds the system should cycle the compressor on for a couple seconds at least. If not, you'll need to troubleshoot if it is an electrical problem (fuse, relay, height switch/sensor, wiring in between components/bad connections) or a mechanical problem (compressor, hoses, bladder on air shocks leaking air).

There is a fuse & a relay for the Electronic Level Control/ELC also called Automatic Level Control/ALC under the back seat in the power distribution block/fuse. Switch out a relay with a similar one and check the fuse for a burnt center section.

There is a ride height sensor attached to one of the rear control arms. With the vehicle safely raised and supported, disconnect the 'link' from the sensor to the suspension arm. With the key ON and engine NOT running, push the arm on the ride height to the compressed/riding low setting. After about 15-30 seconds (it is slow to respond or it would kick on and off over every bump) the compressor should turn on and begin filling the air bladders on the rear shocks.

If the compressor still fails to come on, you'll need to unhook the harness connector at the compressor. Again, with the key ON, engine OFF, height sensor compressed connect a voltmeter to the Dark Green wire on the chassis side of the harness connector (there are four wires to the compressor. 2 wires are for the electric motor to raise the car, and 2 wires are for the Vent solenoid the releases air pressure lowers the car) and ground to see if the compressor is being told to turn on by the height sensor. If it is being commanded on and supplied electricity, and still doesn't make noise or pressure, then replace it off a similar year GM vehicle that has rear air suspension (Cadillacs, Buicks, Oldsmobile Auroras). As long as the compressors are the same, you can just remount it in your car's mounting bracket assembly and save some $$.

If the compressor comes on but the car won't rise, check the air lines to each shock from the compressor, the bladders on the shocks themselves, the filter on the compressor intake or even the vent solenoid assembly on the compressor unit has been known to leak/corrode/stick.

Good luck.

What is odd is the compressor stopping after so short a time. It may be your only problem.

When you have a leak in the system, the compressor keeps running because the sensors do not signal for it to shut off. On your vehicle it is either being told to shut off prematurely or the compressor is triggering a circuit breaker.

There are ride height sensors on the rear. If the vehicle was lifted without turning off the Air ride, the sensors may have been stretched.

You can check for air leaks in the suspension bags, and air lines using a spray bottle of soapy water. There is also a Master dump valve that should be ahead of the Drivers front tire/radiator well area. It is not a concern unless there is no pressure in the system.

Finally, just as the engine can express diagnostic Codes, so can the suspension. You need a better scanner to do this function. It is the quickest way to find the problem.

Please rate my info.

That's the elc compressor (electronic level control) you have a leak in your air system somewhere and its trying to maintain the proper ride height. this compressor is wired to run even with the engine off,if is runs excessively you may have to unplug the wiring connector at the unit ,or find and fix the air leak

The compressor should only run until the rear suspension reaches the desired height. If it continues to run after the suspension has raised to ride height then you may have a leaking air bag/solenoid or line. If you dont have any leaks it is possible the EVO(air suspension module} or relay is at fault.

To begin with, check the "ride level" fuse and make sure that the ride level compressor does work, and you should be able to hear that the ride level compressor is working when the ride level system is leveling the vehicle.

The ride level system uses an air compressor and either an air type of shocks or a type of air billow to raise and lower the vehicle, there is an adjustment to set the ride height and it is located under the vehicle and there is a control lever or rod that should be connected between the rear axle and a switch that is mounted on the body of the vehicle, and there will be an adjustment slot in the control lever between the switch and the body, and that is how you would adjust the ride level height, but be sure that the vehicle can not drop any further down if someone is under the vehicle trying to adjust the ride height.

However, you might find that the control lever to the ride level has fallen off from the switch on the body or it has come loose from the rear axle, and it is just hanging there not operating the switch on the body that controls the the ride level compressor, or there might be a blown out air shock or billow, or you might find that an air line from the compressor is leaking and the ride level compressor will just run continuously until it blows out the fuse, and if that is the case you might also find out that the air compressor has burned out from running continuously.

I hope that this information will help you to solve your ride level problem.

To begin with, check the "ride level" fuse and make sure that the ride level compressor does work, and you should be able to hear that the ride level compressor is working when the ride level system is leveling the vehicle.

The ride level system uses an air compressor and either an air type of shocks or a type of air billow to raise and lower the vehicle, there is an adjustment to set the ride height and it is located under the vehicle and there is a control lever or rod that should be connected between the rear axle and a switch that is mounted on the body of the vehicle, and there will be an adjustment slot in the control lever between the switch and the body, and that is how you would adjust the ride level height, but be sure that the vehicle can not drop any further down if someone is under the vehicle trying to adjust the ride height.

However, you might find that the control lever to the ride level has fallen off from the switch on the body or it has come loose from the rear axle, and it is just hanging there not operating the switch on the body that controls the the ride level compressor, or there might be a blown out air shock or billow, or you might find that an air line from the compressor is leaking and the ride level compressor will just run continuously until it blows out the fuse, and if that is the case you might also find out that the air compressor has burned out from running continuously.

This part is called the auto leveler or air ride compressor. If it has air ride then it is the compressor, If it is constantly running it is possibly the leveler switch that is mounted on the lower control arm that detects the ride height and tells the compressor to kick on.

You have what is called a height/load leveler switch located on rear axle of vehicle .Check to see if the arm (which moves and kicks on compressor when ride height is low) Is connected and moving freely..You then might want to make sure that the air supply lines atatched to air shocks or air bags are not leaking.. If all checks out fine and you decide to disable compressor you can do this by unplugging harness that connects to compressor...And then you can manually adjust your ride height by adding air to the valve on compressor (it resembles a tire valve stem) this will adjust your your ride height and you can let air out at same location if lower height is desired.. This is a little inconveinient but will bypass automatic system as you requested.

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 $$$

The compressor you refer to is the air suspension compressor. It provides air to adjust the ride height of the vehicle. If you will notice by looking underneath the rear of the vehicle you will notice air adjustable rear shocks, or struts. They have plastic tubing plumbed to the compressor under the hood. There is a ride height sensor for the rear of the vehicle attached from the chasis to the rear differential. Whenever the height of the rear of the car is below the threshold setting of the sensor, the system activates a relay and turns on the compressor to raise the rear of the vehicle above the minimum height specified by the manufacturer. As the vehicle ages the air envelopes of the struts loses structural integrity and seepage, or leakage develops. Some depletion of air is normal, but the compressor power supply is independent of the key position, so the compressor can run, and will run anytime the height falls below the minimum. If the car sets unattended for several days, (or weeks) the compressor can run the battery down while maintaining the minimum height. If the system leaks too much air the compressor can burn-out trying to replenish the system. If you notice the compressor runing for an extended period of time, or running too frequently you should have the system checked for the source of the leakage. (Or you can do it yourself with soapy water and a spray bottle by soaking the air bellows on the shocks or struts, and all the lines and fittings from the shocks to the compressor) If you intend to work underneath a vehicle, service stands are mandatory! DO NOT UNDER ANY CIRCUMSTANCES ATTEMPT UNDER VEHICLE SERVICE WITHOUT PROPER SERVICE STANDS IN PLACE AND STABILITY VERIFIED WITH APPROPRIATE FORCE TO PROVE THE VEHICLE CANNOT BE KNOCKED-OFF THE SERVICE STANDS!