well guys and gals . i now know how to repiar vent problem on the blazers . the resistor control the fan speeds the actuator control the cold and hot and the vacuum controls the vent possiton. so there it is guys and gal. no taking dash apart no dealler ship its was all relay and resistor and a big hole in a vacuum hose on the outside was dryrotted with a dime size ho9le and thanks to all of you here and this sight i got her done in 30 minutes thanks again guys