check out the following site
http://flashoffroad.com. if anywhere has the solution it'll be there. or get in contact with Dave at Bluehummer outfitters. there both great sources of info.
You could also try swapping out the solinoids front and rear then see if you rear tires start going down. next I would look for bad hoses or conectors.
before you check anything else disconect your front tire CTS at the wheel hub. this can be done by pressing the little tab on the connector in the center of the wheel. it should pop out 1/4 - 1/2 inch. when youv'e done this leave for an hour or so an see if one or the other tire goes down. if it does it could be a simple puncture or worse case bad rim. If it is a puncture I hope youre not running runflats.