His TC is in great shape, no other problems. Issue just started, when he turns heat on, blows regularly out left vents (as hot as you want). Center vents are only mildly warm, and the right passenger vents are cold, that includes the floor (he hasn't checked defrost vent, yet).
We are unsure what to try. Have read several auto blogs, seen this same question asked, but no answer provided.
Thanks, in advance!
My car has 160000 miles.
My car has an automatic transmission.
Hi there - I suspect you have a problem with the air blend doors inside your heater unit in the passenger compartment. These doors control air flow inside the passenger compartment. A failed or stuck air blend door would result in the air flow issues you describe. I would recommend a heater system inspection by a mobile, professional mechanic, such as one from YourMechanic, who will come to your location, diagnose this problem, give you an accurate assessment of damage and cost estimate for repairs.