I had an aftermarket Kenwood Excelon Navigation unit installed on my 2011 GMC Sierra truck. A few months later I had a local dealership install the alarm system. About a month ago, I started having an issue where my right front blinker and dome lights would not turn on. I checked the fuses and bulbs but all were good to go. A couple of days later everything started working again, but the following day no dice. I took the truck to the dealership and after a week they said that it was probably due to the new stereo that was installed. They said that most people don't know this but the factory radio has a lot of programming stored internally that the truck uses for various operations :no:. Now I have never heard of that and I have never had any issues with aftermarket radios. What do you guys think? Alarm system? They said that they ordered in another ECM and disconnected the alarm, but all it did was short out the new ECM.