Hot air not blowing

[speedhead]

I've put in a new heater core, put everything back. I put the slider on cold and cold air blows out (proper switch position). I put the slider to hot and no matter what position I put the switch in (defrost, heater, vent) I get no airflow. I am getting air through the heater core, and the hot/cold vent door works. Also my A/C shorts when I turn it on (I know this is unrelated).

Thanks

Mike

[Mikz86TA]

Year and model will help out a great deal here.

Welcome to The PLANET!!!

[bespurcell]

X2. It could be a vaccuum line.

[speedhead]

Oh yeah, it's a 1990 4x4 ext cab with A/C

Thanks

[Y NI Rider]

Welcome to the planet.
Check your hoses mihgt be off like mines. Have no heat lol. Theres a few near the underneath of the bumper and behind the radiator.(mines hangin)

[Mikz86TA]

'90 will be cable slider and vaccum lines. Doublecheck them. Its kinda unclear to me the exact issue. Please explain it again and also try it on all modes and tell us what it does. That would help us help you.
Good luck

[speedhead]

If I move the slider all the way to cold, I can get cold air blowing out the vent, when switched to vent, floor when switched to floor and defrost when switched to defrost. The AC slider positions will also blow out the proper vents. When I move the slider to heat, no matter what position I put the other slider (vent, floor, defrost), I get no hot airflow. There is heat coming out of the heater core. The door beside the heater core does open and close.