[Bryan Wescott]

2008 GL 550

My suspension compressor won't turn off. I had it diagnosed and was told my compressor was no good. I replaced the compressor and it still won't turn off. I suspect my first compressor went because it ran too much? I have no leaks and the relay is good. I can even hear the pressure relief valve going off so I know it's building up enough pressure in the system that it should be shutting down on its own (something I couldn't hear on my old compressor). Help please!!

 

[Eric Wesson]

2008 GL 550

My suspension compressor won't turn off. I had it diagnosed and was told my compressor was no good. I replaced the compressor and it still won't turn off. I suspect my first compressor went because it ran too much? I have no leaks and the relay is good. I can even hear the pressure relief valve going off so I know it's building up enough pressure in the system that it should be shutting down on its own (something I couldn't hear on my old compressor). Help please!!

Better act quick. Those compressors don't last long when run continuously. Consider taking out the fuse and replacing when you need to adjust the ride height or refill the reservoir.

I don't know the details but there has to be a pressure switch (on the reservoir?) that tells the compressor to stop and start pumping.

 

[cnpnh11]

Bryan,

The fact that it's running non-stop could mean a few things, but it seems like you've already narrowed it down. Make sure you're certain about the relay (1st step). Soap/Spray test the air springs at each wheel checking for leaks. If one of the bags is losing air, it would naturally cause the compressor to constantly try to fill the bag up, causing it to run too long. If you're not losing air in any of the springs, it could be a cracked air line leading to one of the springs slowly losing air and causing the same problem as if a spring itself were bad. You said you've already replaced the compressor so that probably rules out a bad compressor (maybe) which could also have been the problem. Other than that, maybe a fuse (located in the same box as the relay - front right engine box above the wheel). I went through the entire system in our GL only to realize it was a hairline crack in the compressor itself that was causing lost air and overrunning of the compressor with little noticeable difference to the ride height. We did get the malfunction light coming on from time to time though.

The odd thing here is that the compressor isn't automatically shutting off after it runs too long (4/5 mins continuously) and give you the airmatic malfunction notification on the dash cluster. Is this the case or do you ever get it?