97 s10 blazer a/c problem help!

it is only blowing when the vehical is moving, as soon as you stop it quits working, the speed controls obviously arent working at all.

its a 97 and doesnt have the climate control of the later modles.

befor its started doing this it was only blowing out of the defrost and floor positions, now it will blow out of the correct vent, but like i said only when the car is moving.

Sounds like your blower motor is inop--- check voltage to it- if there when plugged in- then time for a new blower motor....also you have a vacuum leak to or from the reservoir that controls the mode door- look underhood for broken plastic vacuum line- or not plugged in good......