I've searched the archives and I cannot find a clear answer as to what is normal operation on the air compressor. I have complained to 2 different dealers 4 times now that I felt the air comp ran too frequently and kind of buzzed. They both told me this is completely normal operation. Here are my air comp symtoms:
1. No drop in height even after 7 days sitting in parking lot so I don't think I have a leak anywhere.
2. When I accelerate gently or hard, the air comp turns on when speed reaches 25 MPH. I can hear the faint comp buzz for about 1 min or so and gradually disappears unless I come to another stop and comp stops.
Can you guys share your observations on your AR with the air compressor please.
Thank You

But 99% of the time, I've got the radio on. Even with the radio off, the A/C makes too much noise to hear the compressor.

Have I ever heard it? Yes, but it is rare. If I go level 1 to 4 to 1 and use all the air in the tank I can force the pump to come on and then I can hear it.

Oddest sound is when I park the car, unload a heavy load from the back and it "passes air" to level itself.

Some folks have reported buzzing and have tried to find where the compressor is touching the body. I just typed in "noise compressor" in the search box (only allroad) and found 97 posts. You might read those, get some ideas of where to look to see if it is buzzing against something.

Is your system set to manual or auto?

Mine will come on when it cylces but only after it lowers or raises, when the pressure is low in the air tank. But not as often as yours.

It's definately something electrical that is going on and off. I come to a stop the noise goes away. You can actually tell when it shuts off. I accelerate and comes back on once it reaches 25 MPH.

If my tank is low, it can be noticeable as it turns itself on and off in stop-and-go traffic. If the tank isn't low, I don't notice that the compressor isn't running, so I can't tell you how much it runs.

It's possible you have a leak from the tank upsteam of the suspension valving, so the compressor cycles often without any effect on the suspension level. AFAIK, no one has reported that as a confirmed diagnosis.

Park the car.. raise it up to #4 then down to 1 and up to 4 again...do you get the same sound as you do at 25?

Or: Pull the fuse for the compressor and see if you get the noise at 25 again.

<img src="http://pictureposter.audiworld.com/56080/air_suspension_log.jpg">
The pressure will increase when the vehicle speed increases. The pressure will decrease when the vehicle speed decreases by opening the release valve.
'001 '006
Term15 Term30 Speed Starter Compre. PressureRelease Accumulator
(V) (V) (0-250) (ignition on) temp. (0-20) valve valve
V V km/h C bar
13.17 13.76 28 Term 50 Off 36 11.39 OFF OFF
13.17 13.76 19 Term 50 Off 36 11.39 OFF OFF
13.17 13.76 12 Term 50 Off 36 11.39 OFF OFF
13.25 13.84 5 Term 50 Off 36 11.39 OFF OFF
13.1 13.69 0 Term 50 Off 35 11.39 OFF OFF
13.17 13.84 0 Term 50 Off 35 11.39 OFF OFF
13.25 13.84 3 Term 50 Off 35 11.39 OFF OFF
13.02 13.54 11 Term 50 Off 35 7.16 ON OFF
13.02 13.32 24 Term 50 Off 35 5.53 ON OFF
13.17 13.84 34 Term 50 Off 35 4.23 OFF OFF
12.95 13.47 46 Term 50 Off 35 14.65 OFF ON
12.95 13.47 58 Term 50 Off 36 14.65 OFF ON
12.88 13.39 67 Term 50 Off 36 14.65 OFF ON
12.95 13.39 77 Term 50 Off 36 14.65 OFF ON
12.95 13.47 82 Term 50 Off 36 14.65 OFF ON
13.02 13.47 87 Term 50 Off 37 14.65 OFF ON
12.95 13.47 87 Term 50 Off 37 14.97 OFF ON
13.02 13.54 84 Term 50 Off 37 14.97 OFF ON
12.95 13.47 78 Term 50 Off 37 14.97 OFF ON
13.02 13.47 73 Term 50 Off 38 14.97 OFF ON
12.88 13.39 68 Term 50 Off 38 15.3 OFF ON
12.95 13.47 60 Term 50 Off 39 15.3 OFF ON
12.95 13.47 54 Term 50 Off 39 15.3 OFF ON
12.95 13.47 47 Term 50 Off 40 15.3 OFF ON
12.95 13.47 39 Term 50 Off 40 15.62 OFF ON
12.8 13.39 26 Term 50 Off 41 15.62 ON OFF
13.17 13.84 18 Term 50 Off 41 4.23 OFF OFF
13.1 13.69 11 Term 50 Off 41 4.23 OFF OFF
13.17 13.84 5 Term 50 Off 41 4.23 OFF OFF
13.1 13.76 1 Term 50 Off 42 4.23 OFF OFF
13.17 13.84 0 Term 50 Off 41 4.23 OFF OFF
13.25 13.84 0 Term 50 Off 42 4.23 OFF OFF

stop everytime?

I get the same noise when I start the car and drive a 1/4 mile, then again at stops. I am guessing ir runs more frequently but I do notice it a lot. I asked about it and they said "yeah, sorry, nothing we can do about that."

from stop light to stop light on the way to work. on the return trip it doesn't run(the compressor) though the same section.

test are in the spare tire well