2001 Toyota Tundra Owners Manual - Page 165
2001 Toyota Tundra Manual
Page 165 highlights
'01 TUNDRA_U (L/O 0008) If air flow control is not satisfactory, check the instrument panel vents. The instrument panel vents may be opened or closed as shown. For removing frost or fog, it is recommended to close the lower vent when using the "Floor", "Floor/Windshield" or "Windshield" mode. 154 2001 TUNDRA (OM34416U)