I've got a 2001 Buick Regal with a dual zone automatic HVAC system. It's getting colder in Ohio, but when I have the heat turned on, it's not blowing hot. It's not completely cold, but cooler than lukewarm.
First, some givens:
- Cooling system has full coolant
- Engine temp runs at exactly right temp
- Both hoses to heater core are hot when heat is on
My first thought was that it must be the air door actuators. I tried to verify that by watching the actuators while adjusting the HVAC temp control. The passenger actuator seemed to respond properly with the full range. But the driver actuator seemed like it wasn't moving the full range and almost like it had some hesitation. But even though the passenger actuator looked like it was responding properly, the passenger side air didn't feel to me like it was as warm as it should be.
Questions:
- Pretty sure I need to replace the driver side actuator. Most choices from Autozone are $100+. I can get them from Amazon for $20. Would I regret the ones from Amazon?
- Could I still have a heater core issue since I wasn't getting warm air on the passenger side? Should I just replace the actuator to see if that resolves it before taking on the heater core?
Can you reach the dampers to help them reach open and closed positions? If damper is sticking you might give a little nudge for correct positions.
@jimz
Sorry to ask a dumb question - but is the damper the same thing as the air door? If it is, then no, I can't really reach it or fiddle with it. I'd have to remove the actuator to get to it. And from what I've read, since this is an automatic system, trying to force it would likely cause some issues with the BCM.
The blend door actuator is not functioning. Whack the dash (near to that faulty vent).
@yaser
My old 55 Ford had so many whacks it looking like orange peal. Sometimes it worked. Sometimes it didn't. 
@yaser
I whacked at it when I was watching it. Didn't make any difference. Pretty sure that actuator needs replacing.