The blower motor comes on full when I turn the key to on, before I start the car. And this is when the climate system is "OFF" And when the car starts, the fan still is on high and never shuts off. I have not tried to diagnose it yet, as it defies logic. I have changed a few Blower Control Modules (BCMs) in the past when they only worked in the full or top setting, but I have never had one that came on full even when the climate system is off. Let me know if this issue rings a bell with anyone, as it has me stumped right now. Also the issue came out of the blue, with no changes or much of anything happening to the car lately., 93 SHO originally ATX, converted to MTX 10 years ago.