I have an 07 CX-9 Grand Touring and had the same problem with mine. The problem is the the small ribbon cable the connects the lcd to the dvd unit. This ribbon cable can't handle extreme temp. and becomes dry and brittle over time. Removeing the overhead dvd player is rather easy. There are't any screws that hold the housing on. if you can get your finger tips between the roof and the housing (starting on the sides towards the front on the dvd player and slowly working your way around to the back. Use a firm - steady grip but don't over do it. after the houseing is removed it's smooth sailing, 4) 10mm nuts, 2 screws and 2 wire connectors.
As for the cable, I found the one I needed @ digikey.com. (1-800-344-4539) I ordered 2 different ribbon cables (I wasn't possitive which was correct).
The first is: HFF-40U-05-ND ($5.45), the second is: WM10238-ND ($5.34). I just ordered today...I'll let u know how it goes.