No sound from radio, although door chimes still work

Yes indeed, radio does get power. Sound has been working intermittently and seems to need to "warm up", (I live in Alaska, and it's getting below freezing already) and will crackle a bit and eventually clear up and work fine, til usually the next morning when I go to warm the car it will be silent with power to the radio, with the exception of the chimes, those still work. I have noticed wetness in the rear passenger floor, and have recently had a coolant flush/ heater core backflush because of overheating, before that water pump and then elbow shaped pipes/tubes replaced that had deteriorated through. Not sure if the shop messed with the blower motor area because they did call while it was in the shop saying it was "acting up and going out" and on another call later that day said they had gotten it working again. I read somewhere that the wetness at the rear floor may be all relative. Hope that makes sense, LOL. Thanks.

-Danny