Heater stops heating after 20 minutes

[Spectre82]

I have a 2012 Pathfinder, bought in the summer of 2020. The first winter I had it I wouldn't get heat till I started driving. After a coolant flush at the local quick oil change place the opposite started to happen. Now The car warms up fine, but when I drive for a little bit the heater stops blowing warm air. If I turn the temp up to 90 degrees I get HOT air. I changed the ambient air sensor in the grill already and that didn't make a difference. Does anyone have a suggestion?

[VStar650CL]

If it has auto A/C then chances are either your cabin sensor or intake (evaporator) sensor is bad. Cranking it to 90 is an override. You're basically telling the HVAC, "Disregard the sensors and make it as hot as possible."

[Spectre82]

Thank you for the info. I changed the cabin sensor, which was a little tricky to get at. It was packed which dust/dirt. So...to anyone else with a similar problem....try a shop vac on the access vent first. This could save you $50 and a bit of aggrivation. So far the heat has been working like before. Doesn't blow warm air till I'm driving. I'll take that over the other one problem any day.