No Heat?

[samwise68]

hey all,

first. i have searched. but was hoping i could find a more specific answer to my question.

on my GMC, there's very little heat. and, since i live in Wisconsin, this is a problem. lol.

after letting it idle for about 10-20 minutes, the vents just don't blow much heat.

the heater core is fine, as both hoses coming to and from are warm to the touch.

so, what can i kinda look at to be the culprit?

a resistor? a bad relay? control panel not opening up all the way?

any ideas would be great.

thanks all!

-Sam.