My factory radio in my 2007 started acting up. Sometimes it works and sometimes it doesn't. for instance. Some mornings i can drive to daycare to drop off my son (average 25 miles) and radio works fine. I can shut vehicle off to take my son into daycare and sign him in (roughly 5 min.) come back out and start tahoe and the radio does not even come on, there is no power what so ever to it. I then can drive it to work and come back out at lunch and it works. any suggestions.