2006 cold air below 2k rpm

i was told there is a resistor that could be cuasing this. im hoping its not the climate control...i replaced that once already and it wasnt cheap. i could leave my truck on for hours in park and no heat will come out til i drive and start hitting 2,000 rpm or better. any suggestions?

Are the hoses to the heater core getting hot when you are in park and the engine is fully warm?

I wonder if you have a partially clogged heater core or a worn water pump and coolant is not flowing thru the heater core until the engine speed is higher.

//2000CAYukon

hmm..i wasnt even thinking that....just assumed it was electrical since ive had problems before. im out of state now..but when i get back to NY i'll check out the hoses leading to the heater core... 80k mi..i supose its possible the water pump is shot. but ive never had the car come close to over heating.

:headshake