2001 s500 airmatic problem car air compressor stays on long and the car is very high

http://www.mercedesmedic.com/mercedes-lowers-drops-parked-air-suspension-self-leveling-problems

I suspect that it is not the compressor as it is filling the system
I would be checking for non return valves in the system that is allowing the pumped air back to the compressor and not storing in the air bags or accumulator tank
to answer your question , the car should not sink down as the non-return valves should hold it in place but if you are concerned jack up the car and place it on jack stands so that the weight of the car is not on the air bags

It looks like this should help:

Where is the relay for airmatic suspention pump on 2000 Mercedes S500

If pulling that out and putting it back in doesn't help, here's some more troubleshooting info:

2000 S500 airmatic problem Mercedes Forum Mercedes Benz Enthusiast Forums

Usually when they stop working it is because they have burned out from running too much due to a leak. Sometimes the leak is on the pump itself at the older T line fitting on the side. If it is the new one with the updated line and it is still running, chances are there is a leak somewhere and that is why it continues to run. It could also be the relay. Usually when I replace the pump, I replace the relay as well. Try a new relay, if it continues after that, you will need to have it properly diagnosed by someone familiar with the airmatic system.

Hi. If the pressure can build up but doesn't hold when the car is off and doesn't leak air, check your air relive valve for debris or electrical problem. Try switch it with other side. If the problem go with switched valve - replace if not you may have an electrical problem with it.

wires that run from the door to the cab get bent back and forth till they break/ almost bet you find one if ya take the rubber off

Your load control sensor under the vehicle is broken or has become disconnected so it thinks you have a heavy load and is constantly running the compressor. you have get under vehicle and look for the sensor it is connected between the rear suspension and the body.

possibly faulty airmatic compressor witch is located under the front right bulkhead, It could do short circuit that could be the reason battery get damaged because of it getting high amps all the time when it's working it can harm to battery check airmatic compressor now it should be dead,

You must go to the dealer workshop for replace shock in your car, after replaced shock in your car must need to re calibrate the airmatic suspension through Mercedes diagnostic CPU otherwise It won't be working properly,

souds like air bags in ridding systen have a leak