I have demon in my dashboard.......Sometimes after a hard rain the radio/CD HVAC lights blink on and off and a crackling sound is heard when are all OFF. Now a month or more the blower box is making weird noises w the switch off, sounds like a mouse is scratching inside the box. If I turn the fan/heat/ AC on and the blower and the AC/heat works fine and no weird noises @ any speed from the blower and it blows low or fast cool/heat when adjusted. Now there's a crackling/scratching noise all the time when the the truck is running w no fan or heat or AC on. I know the windshield was replaced on the 98 K1500 and I wonder if rain is leaking under the dash. I can't find any wet spots under the dash or the floorboard but sometimes the glass fogs until I turn the defog on when it's cold. I'm also slowing losing coolant from the jug, but I don't smell any antifreeze in the cab w the windows shut. Any advice about this is appreciated.