DirtySCREW is acting up. She's a 2003 Lariart FX4 model. I have the fancy automatic HVAC system. It got a little cool here so I put the heat on. It was blowing cool. Waited for the truck to warm up and I could only get heat on the "PNL/FLR" button. If I changed it to DEF it would be warm, but VENT and FLOOR would start to blow hot then go to cool.
On the PNL/FLR setting it is HOT! She's always had a good heater.

I'm thinking my HVAC unit is going bad; but what do ya'll think?

Heater core?

heater doors not opening?

Thanks in advance.

DirtySCREW

 

anyone?

DS

 

I'd start by doing the Oring rebuild on the headunit. Cheap, fast, and easy.