I recently changed out my heater core. After putting everything back together I noticed that the drivers side (left vent) in constantly blowing out hot air. WITH THE A/C OFF, the center vents, passenger vents and lower feet vents all blow semi cool air. The driver upper vent just blows hot. WITH A/C ON, the driver side vent is only slightly cooler and the rest of the vents are marginally cooler than with a/c off. I did adjust the air recirc cables underneath for the dash and made sure the valve in the engine was closing fully. Is there a specific vent flap for the left vent in the dash that is maybe stuck open somewhere? I'm guessing an A/C recharge is also in order?

 

Best to fix the air mix issue first because the A/C is possibly fine.

This may help:

 

How do i go about troubleshooting this? It is only the vent to the far left causing the problem. The others all are blowing in the correct order.

 

If you turn off A/C and turn on the heater, where does heat blow in the vent, heat/vent, floor, and hot/cold modes?

Fixing may require removal of the dash again.

 

I took another look, the air flow in the first two pics is correct. In the vent position all upper vents blowing air. In the heat/vent position air blowing out all vents. Strange though in the foot only position, the driver vent still blowing but all other upper ones no air flow.

 

Some models have a lever under each vent on the end of the dash which admits outside air direct to only that vent regardless of the other controls. There is no fan involved, it uses the ram effect when the car is moving.

 

Is there a picture for just the feet venting?

 

What controls the flapper that opens and closes against the heater core? I have a feeling something is not closing properly