Second unit (returned first) but same pro...

First unit I owned of this model had to be returned because the DVD/CD would not play unless I ejected the disc 2-10 times and then it would just work. (The screen would just flicker) The radio component worked fine during all this - so the problem was localized to the DVD/CD. Needless to say, pretty annoying to have to do this constantly.

Returned it for a brand new unit and the same thing is occuring with this one. Could this have something to do with installation? I connected the parking brake wire to ground so it can be viewed while driving - not sure if this could have something to do with it.