97 Continental...air ride not working

Hey all...hope I can get some help with this!!! I have a 97 Lincoln Continental and the air ride has had a leak because for a while now the rear would sink when parked. As soon as started it would air up...no prob. It started airing up and the check suspenion light would come on but usually stayed aired up...would sometimes go down while driving though. The compressor would also come on while it was parked in the driveway from time to time. Well yesterday...the compressor didn't come on at all. My hubby had it checked and they stated that there is no power getting to the compressor or to the leveler in the back of the car...but they could jump it off the battery and the compressor would come on. What could be wrong and how do I locate it...and then fix it!? I have to use my car daily for work and getting kids to school. I can't afford a conversion kit to change it to springs...we live basically paycheck to paycheck and a hell of a lot of praying that it stretches far enough. I can get a little money to fix it but not a lot! Please help!! we know nothing about these things.:crying::runaround:

Almost forgot to add that the front is fine it stays up all the time. And I have heard that these cars have both front and rear air...or is only the rear air ride?