Sounds like the "blend door" is not working as straybullitt mentions. Is it cool when you first start the Jeep in the morning, then turns warm as the engine has been running for a few minutes?
Some vehicles (early Dodge Trucks) have this common problem. What year/model is your Jeep?
Try googling it (i.e. Jeep blows warm air with AC running) to see if it's a common problem, and to point you into a Jeep forum for further answers.
It is better to keep your mouth closed and let people think you are a fool than to open it and remove all doubt.