WE RE DEAF COUPLE AND BOUGHT 2008 BUICK LUCERNE WHICH WE CANT USE ONSTAR OR AN EMERGENCY PHONE CALLS... I HAD BEEN TRY CALL THEIR TTY BUT NEVER ANSWER ME AT ALL.. SO WE WENT TO KARP COMPANY FOR CHANGE OIL AND FILTER.. I MENTION TO THE GUY ABOUT ON STAR WHICH WE CANT USE ANYTHING WITH IT.. I ASKED FOR IF ITS POSSIBLE TO ADD BACK UP TV SCREEN WHICH OUR BACK OF HEADBOARD ARE HARDLY TO SEE BACKGROUND...THEY SAYS ITS MIGHT COST US $750.00 .. OH BOY !! HOPEFULY U CAN HELP US WITH IT.. MANY THANKS !!