2004 Dodge Stratus

OK, I have an 04 Stratus SXT. Twice now I have gone to start car and no radio or ac/heat or alarm. Everything else works fine. First time I was driving and parked in lot and when i tried to set alarm, nothing. I then got back in car and radio, ac/heat and alarm were the only thing that quit working. Repaired at dealer and several months later, Car was sitting in lot at work for 10 hrs in about 90 degreee heat and same problem. After driving 20 mins I restarted it and everything was fine. Any suggestions?

park in the shade?

Almost sounds like you a short in the wiring. I'd take it back to the dealership ship and have them check it out since it is probably still under warranty