92 s10 heater does not go to defrost or floor only vents not equipt with a/c

SOURCE: Heat wont blow through heater or defroster vents

Had the same problem. believe it or not i changed the gas cap and got heat all around. something about pressure.

SOURCE: heater control 98 chevy s10 blazer

These trucks have a problem where moisture builds up in the heater box then freezes. When this freezes and you change your heater settings it breaks the shaft for the blend door. If this is what happened you should be able to look under the dash above and to the right of the gas pedal and you will see two vaccuum accuators one of them you should be able to wiggle around the linkage if it is broke. To fix this you need to remove the entire dash to get the heater box out which involves discharging the AC and draining the coolant because the heater core and evaporator come out. Please rate.

SOURCE: Heat wont blow through heater or defroster vents

common problem, check under dash by the gas pedal if control arms are muving went selecting from ac to heat cuz this it is the control for the vents to go from ac to heat and to defrost.

SOURCE: vacuum leak

I have a 1992 chevy blazer s-10 type my heater blowes through the defrost and floor will not blow through vents on dash can you please help with problem thank you frank

SOURCE: Heater blows out dash vents only. Will not blow

Sounds like the switch that closes and opens the door for the changing of air flow is bad.

Testimonial: "Thanks, this is the way I will head for repair."