[Cadillakin'98]

99% of all electrical problems are linked to a faulty ground. Think about the way a switch works.........doesn't a switch ground out and/or completes the circuit? Don't have my wiring diagrams nearby but I bet if you looked you would see how the fan switch will complete the ground (circuit)- that is when it works properly..............You mentioned the blower motor comes on only when you put the switch on high, mine was doing the same thing. Have you ever tried jigglling the switch around to make the proper contact to make the blower motor operate at a lowerer setting? I would have to "play" w/my switch for awhile to get it to a lower setting when desired. One last question...when switch is in the off position, and you have the AC button pressed in, does the AC button light remain on??? Try that, I know you said your in Michigan where you may never even use the AC but I'm from Texas and thats how I figured out it was my switch because I knew that when the fan switch is in OFF position, the AC button light (indicator) should not remain lit. When AC is selected, indicating light should only light up when you turn the fan on. Try that if you haven't already. I'm telling you it took me a little while to figure out that even though the switch is off and you can't hear the blower, the unwanted annoying air flow was due to the faulty fan switch and as mentioned, this is a very common thing. Let me know.....