For the last two mornings, and only in the morning, when I go out to start my truck and I hear the noise of what should be the grid heaters firing up, my radio turns off. And it wont come back on for a couple minutes AFTER I've started the engine. It wont do this in the afternoon after work - maybe its warm enough that the heaters dont cycle. Temps here are in the low 50's overnight... . anyone else notice this????