My AC has been out for about 6 months, never really needed it so never bothered with it. But just recently my vents stopped working, as far as the fan that is. I've noticed that on the highway it will blow medium strength (I guess from the wind pushing it through?)
I've also noticed an electric whirring sound when I switch the vents on and off (like a really subtle grinding.)
Any ideas of what this might be? The free way thing made me think an electrical issuer for sure.

 

Could be the resistor on the heater housing, or a bad blower, or a bad control switch. Try running wires directly to the blower to see if it works. If it works I'd say check the resistor.

 

Gotcha, I'll give it a try this weekend. Thanks

 

sounds to me like the vent doors are not working correctly.highway your alt is putting full poer and vacume is strong