Why do my car speakers sometimes sound busted, but at other times are fine?

[85rockstar66]

I drive a 2007 Chevy Silverado Crew cab with a factory installed XM/CD radio. Recently I've noticed that the speakers in the front doors sometime sound busted. Now the back speakers don't work at all and the front speakers work when they want to. I've noticed that the front speakers (except the tweeters) don't work when the vehicle sits in the rain or in the morning when it is still cool outside. Sometimes they work without any problem once the outside temp goes up. I don't know if temp. is really a factor because it doesn't always help the situation.
I disconnected the speaker and XM wire whip from the back of the stereo (to see if there was any corrosion inside the connectors) and connected it back together. Now I don't get the door chime or key chime. Does anyone have any thoughts about what my problem might be?
Thanks, Rich

[PaulD]

factory speakers only last so long and so do factory radios. Yours may be at it's useful end.