Heater controls on 2000 Chevrolet S10

Why would I not be able to get hot air from the heater when engine is at normal operating temperature?

3 answers 1 comment
you could have a defective or malfunctioning temperature blend door. Its job is to direct the air over the heater core, so it gets warmed up!
Thanks for the response. I was thinking maybe the control in the dash. If one were to check the blend door you mentioned, where would one find it, firewall or under dash?

I know on my 2000 Silverado, the entire dash had to come out to replace my heater core!
thermostat
Sounds like your heater core is air locked, and it just needs to be back flushed.