heat! on 1993 Nissan Altima

I have no heat! replaced resistor, all fan settings work, a/c works. Coolant is at proper level. does this just leave the heater core or is there something else i can check before that huge job and expense????

Asked by for the 1993 Nissan Altima
1 answer 1 comment
Make sure your heater control valve is actually opening.
where is the heater contriol valve located