Heater blows in one position does not switch from windshield to floor

Hello, Dave here, contributing to RepairPal and providing expert advice since 2010. This vehicle uses engine vacuum to feed a mode door motor. With a motor issue or vacuum supply issue - the mode will not change as desired. Testing of the vacuum system and related motor is needed to find out what is going on. Gently shared - I would not have wasted time, money or effort throwing a part like a control module at it to fix it -- it is best to understand how the system works and then perform needed troubleshooting to get to the source of the problem. A simple disconnected vacuum hose, for example, could be the cause of failure. But you'll have to investigate. To get a shop near you to help out -- https://repairpal.com/auto-repair-near-me Click the link or call us at 877-913-1554. We'll gladly find you a certified RepairPal shop in your area.