My 2013 expedition has air suspension ride and the rear bags deflate completely and randomly. Typically to reset all I have to do is to turn off the car, open/close the drivers door and start the car gain. On at least one occasion I have had to disconnect the battery completely. Dealer is useless and can't find the problem as it is intermittent. The two rear bags deflate equally and when this happens the motor never stops. My first thought is the solenoid valve or dryer. Any ideas?