Check the switch/valve in the seat panel. It could be just sticking in the open position. Remove the seat side panel to remove the switch/valve assembly. Then disassemble, clean, lube (light oil is fine) and reassemble it. The reinstall is a little tricky because of the air line connections, but a little patience goes a long way. It took me about an hour to remove, clean, and reinstall mine. It works just like new again.