Re: 2000 ford focus vent issues
Not to sound stupid, but define nothing happens. If the air doesn't divert, your diverter door is not moving. If the AC stops working in other modes, you have an electrical control problem. From the initial description, I'm going with electrical.
When in defrost, the control module turns on the ac, regardless of temperature setting, to act as a dehumidifier. So either the switch is shot or the heat control module is not recognizing other modes.
Chewing on asphalt and drinking dinosaur wine