mlsins

My wife drives an 04 GX 470 and will not let me trade it. She LOVES it and has driven it since new. A problem has come up that I cant figure out. The rear air compressor has stopped coming on so the rear end is riding low and very rough. I searched the old threads but couldnt find much info on this problem. Anybody out there have any ideas or do i just need to go see the dealer? I've tried adjusting the height control, turning it off and on, etc... No luck. HELP !!