XM radio loses signal after car is shut off
 

(2009 Sante Fe)I have had the dealer replace my built in radio/xm unit 3 times in the past 7 weeks due to the fact the cd charger was busted and then XM would not work. Xm has verified that everything on their end is ok and has suggested that the dealership has not install the new radio(s) properly. I can activate new radio and get XM until I shut the car off , then I am back to the normal 0,1 and 247 only. Any suggestions on why the unit is reseting all the time ?