Have had this truck for about a month. Runs great, two owner, well taken care of...This seems like an odd issue but sometimes I put the key in and truck does nothing, security light is on, lights on, radio will come on, no other sounds, no clicking nothing..I thought that my key chain might be interfering with whatever device is in the key and the ignition so I took those off. It worked for a while, now this morning it happened again. It is very cold here and when I realized it would not start after several tries I waited about 10 minutes and put key in again. Truck started right up. I have had the battery, alternator, starter checked-everything fine there. No check engine light. It seems to be something with key?? Also checked with Cadillac dealership service department. They said maybe a sensor/chip issue??? Any suggestions?