Where is the relay for the compressor located?

  • 2008 MERCEDES BENZ S550
  • V8
  • 4WD
  • 181,000 MILES
Car sits right, actually based on scanner readings the front is higher than it should. If you are parking and the car is on, every few minutes you will hear air relief from the front right. It is sitting high. Left is sitting the highest. I replaced the air compressor in case they all failed. Still gives me air ride malfunction and same message, that the compressor is taking too long to fill. Here are some readings. The rear is okay, but I am trying to figure out what it is that makes an air strut go much more in height than when the pressure is released it drops down some, but still not even close to where it should be. I also have a new relay for the compressor, I just don't know where it's located. Front left reaches.70. Sometimes both front reach 0.512 which is still much higher so I know it is not the struts. No sinking in any of them. While driving front left around.3.5 front right can reach 1.4 inches. Car also after its warm acts like it's hard to start before it turns over, take one turn, pause then turns over. Never fails to start. Weird thing battery under hood measures 13.26 while car is off, never seen that before.
Do you
have the same problem?
Thursday, August 4th, 2022 AT 8:31 AM

1 Reply


I attached the wiring schematic below for the suspension circuit. What I'm seeing is the relay that controls the Airmatic compressor is in the front SAM fuse and relay box.

I attached the wiring schematic below for the circuit. (Pics 1 and 2). Pic 3 shows the fuse that powers the compressor.

Pics 4 and 5 are to help you locate the compressor relay.

Here is a link you may find of interest as well:


Let me know if this helps.

Take care,


See pics below.
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Thursday, August 4th, 2022 AT 6:27 PM

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