Inspect Heater Control Dial And Lever Operation.
WARNING: This page is about a different car, the 2002 Toyota Tundra. However, it is still accessible from the selected car via links, so may be relevant.
- Move the control dial and lever left to right and check for stiffness and binding through the full range of the levers. If click sound can not be heard or recoil is felt, adjust the control cable or check control cable and heater control assembly.