Why won't my Jeep Wrangler's heating and cooling system work properly if the AC makes the air cold and the heater makes it hot but the air will only come out of the windshield vents?

Answer 1

There are many aspects to the in cabin environment controls.
The fan on/off and speed controls, temperature controls, and where the air direction controls are separate.


The controls that determine where the modified air are directed are sometime of the slide control variety, a lever that pulls or pushes a stiff wire connected to dampers that allow or restrict air flow and there by directing it. Some vehicles have vacuum actuated air damper controls, push buttons or a slide lever change air paths in the control module that causes dampers to open or close and thereby direct the air flow from the fan motor.

If the slide lever doesn't move easily or too easily the wire may have become detached. Sometimes vacuum hoses fall off under the dash and will cause like problems. In this case you may hear the sucking sound of the hose. Check your local library for a service manual about your make and model of vehicle. repairs of the heating and cooling controls are usually easily affected...