electrical problem

Does the display stay on on the radio and just lose sound? If so I have seen this problem many times, there are 3 harneses that go to it and the ones on the left side (when looking from the front) send the signal to the amps and that plug does not stey in the radio to well, I usually reinforce it with duct tape. as far as the air only coming out the def vent I would check the vaccume junction under the glove box close to the center console. It has several lines going in and out and I cant remeber if its black, blue or red that feeds the valve but they come out pretty easy if the junction gets jarred. The hoses are tight so see if you have one not connected or loose. If you did knock it loose before and just plugged it back in make sure its in the right spot because there are a couple spots not used on it. If that is not it make sure the line going to the vaccume can is ok (its under the passenger side fender) hope it helps.

Sounds like they went ahead and used the wire kit for it which means its going through the factory amps still. Personally I would run all new wires from the deck to all the speakers because if its a good deck the internal amp is way better than our stockers.