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AC works on defrost setting only

My AC is not working on any setting but defrost. Warm air blows out on the reg AC settings, but if I turn it to defrost, chilly air comes out. Any ideas?

That would point to the AC switch or associated wiring. The defrost bypasses this switch on some cars.

The door that directs the air to either defrost or cabin position is either stuck or motor is dead. This may use vacuum depending on the year. A vacuum leak would cause the door to no move either. My 95 Dodge did this and needed a little motor, $85. My old 77 Chevy did it and I had a vacuum leak. Depends on what you have.