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What is humming when the car is off?

lindahelindahe Member Posts: 5
edited October 2017 in Buick
My mom is 91 and drives a 1993 Park Avenue. When we were chatting in the driveway with the car off and the keys in her hand, we noticed some humming from under the hood. It runs for about 10 seconds and then shuts off...tracked it to a part next to windshield washer fluid. The part is kind of silver in front; kinda horseshoe shaped with a black part in back looking like a mini megaphone (sorry for the terrible description). Mom says she sometimes hears it doing this when she walks into the garage. Is this normal??? Any help would be appreciated...when she or I go to a local place, they always seem to "see us coming".


  • 0patience0patience Member Posts: 1,712
    Can you take a picture of it and post it?
    Depends on what it is. If it's part of the cooling system, it's possible for something to run on after the vehicle is off, but the description kind of sounds like the horn, so not sure.
  • lindahelindahe Member Posts: 5
  • lindahelindahe Member Posts: 5
    Thank you so much for responding!! It's the part in the middle with the purple wire...
  • thecardoc3thecardoc3 Member Posts: 5,745
    That is the level ride air compressor. It's normal to hear it run at times, but should not need to run continuously. If it is running a lot then you may have a leak in or to the rear air suspension.
  • lindahelindahe Member Posts: 5
    Thank you! Is this dangerous if not fixed? It seemed to go on every 15 minutes for about 10 seconds while we were in the driveway. Pardon for me for being blonde (!), but what does it actually do?
  • 0patience0patience Member Posts: 1,712
    Sorry I didn't reply earlier (I often work in areas with no internet or phone), but @thecardoc3 has it covered.
    Agree that if it runs quite a bit, there may be a leak.
    But, the only way to tell for certain is to see how often it runs while sitting.

    The ride leveler is what levels the car when a load is put in the car/trunk. It "sees" the height of the car and will apply air or release air to level the car or bring it to the correct height.

    When you put something in the trunk or someone gets in the car, the sensor tells the pump to start.
    The pump supplies air to the rear shocks or air cushions and lifts the vehicle to the correct ride height.

    That's the basics of it.

    If the rear of the vehicle is low, then it could cause handling problems and it should be fixed soon.
    If you are in an area with a good tire shop, Goodyear, Les Schwab Tire(west coast) or one of those, they can probably take a look at the lines and shocks for a nominal diagnostic price.

    Another concern would be that if the pump runs too often and the vehicle isn't run for several days at a time, it can run the battery down and shorten the life of the battery. Which while not considered a safety concern, can be expensive and an inconvenience.
  • lindahelindahe Member Posts: 5
    Bless you for taking the time to explain all this to me! I will take the car in and have it checked; I feel so much better about doing it, now that I have a clue. Have a GREAT day!!
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