Compressor for rear shocks not working

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Suspension, Brakes and Tires Discussion, Compressor for rear shocks not working in Item Specific Cadillac Discussion; I have a 2004 Deville (base) with 140000 miles. I have read everything I can find on this forum about ...
  1. #1
    Trouble is offline Cadillac Owners Member
    Automobile(s): 2004 Deville
    Join Date
    Nov 2011

    Compressor for rear shocks not working

    I have a 2004 Deville (base) with 140000 miles. I have read everything I can find on this forum about the rear suspension but still have some unanswered questions. The air compressor does not come on. My wife and I sat in the trunk with the key on and the compressor doesn't do anything. So the next step would be to check the fuse. Which fuse is it? I have looked under the rear seat and under the hood. The only one I can find that might be the one is under the hood called Air Pump. It is a 50 amp fuse and does not appear to be burned out. Most of the fuses are labeled with some letters that mean nothing to me.
    Some time this summer I replaced the rear shocks with (I think) Monroes from Advance Auto Parts that were a direct replacement for the OEMs. If I remember right they were about $100.00 for the pair. Some time later one of them failed and Advance replaced them. I don't think the compressor was working then. So unless it is just the fuse I guess I am in for some expense repairs.
    Am planning on taking a trip later this month with another couple so need to get this fixed. Right now I don't have that Cadillac ride with passengers in the rear seat.
    So I need to know where the fuse is and where the compressor is. And from what I have read here I guess Sunpro (I think it was) is the best place to to go for a compressor and I guess a dryer (whatever that is)???
    Thanks for your help.

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  3. #2
    Submariner409's Avatar
    Submariner409 is offline If it won't run, chrome it
    Automobile(s): 2002.5 F55 STS - 67,500 miles, 2014 Explorer XLT FWD
    Join Date
    Feb 2006
    MD Eastern Shore, Kent Island

    Re: Compressor for rear shocks not working

    New OEM rear shocks for your car are a LOT more than $100/pr. A LOT. SUNCORE or Amazon Automotive for the Level Control compressor, located up in the RR rear quarter inside the fenderwell liner. Sensed by one or two height sensors on the wheelwell body metal - connected to the suspension arm by a ball joint link - they have become unsnapped........

    If you get in the car, turn the key:ON and sit - about 10 seconds later you should hear the compressor do a preload of about 2 seconds. If you have no DTC's (Diagnostic Trouble Codes) in the car's built-in code reader/scanner (2004 still have it?) and the compressor does not run, obviously something's wrong.

    The filter/dryer removes compression moisture from the discharge air and blows it down during lowering sequences. It eventually becomes saturated (It's a hidden service item) and allows brown snot to rot the compressor/exhaust valve head.

    Fuse is ELC or ALC. (AIR pump lights off the cat at cold start) and is in the fuse box under the rear seat, driver's side.

    Discussions, Item Specific, Cadillac Tech Tips.

  4. #3
    Trouble is offline Cadillac Owners Member
    Automobile(s): 2004 Deville
    Join Date
    Nov 2011
    Thread Starter

    Re: Compressor for rear shocks not working

    Hey submariner409 thanks for the help.
    I tried checking the fuse but had no idea which one it was. I will check that tomorrow. Did the preload test and the compressor did not run. Have no idea if there are any codes but maybe there is something in the owner's manual about how to check that.
    I did replace the rear shocks this summer. Got them at Advance Auto Parts. I just looked on their website ( and the ones I got must be the Monroe Max Air for $75 each.
    Again, thanks for the help.

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