Heater Confusion

I have a 2000 jgc 8cyl and my heater works fine on the drivers side but blowing cold air on passenger side. The dials work but the air is split down the middle of the cabin. Any thoughts on this confusing topic would be helpful, Thanx Roc

The blend doors divert, not block air, so it is unlikely that the blend doors are the problem. You need to check the operation of the re-circ door. Hopefully the mechanic had enough sense to replace the re-circ door while it was apart and easy.

Blend doors are small airway control doors that move into positions to blend hot and cold air
to your liking based on where you have the temperature setting knobs positioned. These little
plastic flap doors hide behind your glove box in your A/C system's housing, and move up and
down to pass heat or cold air as you command.

The material has caused them to be weak and brittle allowing them to fall apart leaving you
with icy cold air as the only option. That's fantastic if you live in Florida or Arizona in the
summertime but for the rest of us we are going to need our heater