The heater blend door is not run by vacuum. It is run by an electric actuator.
The 4x4 actuator is screewed into the front differential housing towards the passanger side, It has electric wires going to it,
the temperature control actuator is on top of the heater box under the dash. you have to remove the dash to get at it. a repair manuual will show what screws to remove
how to replace a heater core in a 1997 Chevy blazer
Remove the dash assembly to gain access to the blend door actuator.
Under your battery tray
on the front axel
The 1997 Chevrolet blazer actuator switch is located on the firewall in the engine compartment. The switch is on the passenger side of the engine compartment.
It could be the actuator that diverts the air through the heater core. Our enthusiasts forum may be able to help you more at www.trailvoy.com
No, it is electric
Changing the heater temp blend door actuator requires removal of the dash assembly. Big Job. You will need a shop manual to attempt that one.
Yes it could and so could a stuck open thermostat or a plugged heater core or a faulty temperature blend door actuator.
It does not use a cable. The heater blend door is operated by a electric motor. The complete dash assembly needs to be removed to gain access to the unit.
The temp blend door actuator is probably at fault.
under the battery plate
The heater temp blend door actuator is located behind the dash assembly, attached to the top of the HVAC box. Unfortunately, the entire dash assembly must be removed to gain access.
Low on coolant (leak in coolant system) Thermostat stuck open Heater core plugged Temperature blend door actuator failure Vacuum supply to HVAC dissconnected
You have to completely remove the dash to get access to the heater core.
Located under right kick panel
pull the handle down
the heater core, heater core hoses or heater control valve is leaking
electric actuator (range selector)
Maybe a bad switch
Right under the throttle cover.
you probably have a bad heater core.