Rear air shocks?

Hi - for some reason I no longer hear the shocks filling up when weight is added.

Is that a problem with the shock(s) itself or is there a compressor motor of some sort that is not functioning? Or bad air line?

Any feedback is appreciated.

thx.

could be a few different things...there is a fuse under the seat for it,its marked "elc" electronic level control ...there is a small wand 2" around the rear wheels in the center of the car that often comes unhooked after years of wear...i have allways found this set up a nusance i replaced the shocks used the kit provided to just add air if ever needed with a bicycle pump and never have to hear that pump running ....news

thanks newscarver, I'll check the items.

I am going to replace the shocks anyway, that'll give me a better isea as well.