I installed a Kenwood KVT-512 headunit about 2 years ago. Now the touchscreen does not respond to any touch at all. I pulled open the screen and reseated all of the ribbon cables that were present. I even did a resistance test on the touch screens which showed it was responsive to touch. Anyone ever seen any problem like this? Thanks!

 

Have you tried resetting the unit, either through a reset buttton on the face or pulling the power plug out for a minute? If this doesn't fix your problem unfortunately you may have to send out to get service.