AC blows hot

Hello,

It sounds like you have a temperature blend door actuator that needs to be replaced. When these go out it causes the heater to come on. Here isa guide to help you see what you are in for when doing the job.

https://www.2carpros.com/articles/replace-blend-door-motor

Here is what it will be like for your car (below)

Please let us know if you need anything else to get the problem fixed.

Cheers, Ken

Air Conditioning problem
2001 Mercury Marquis V8 Two Wheel Drive Automatic 100000 miles

Replaced Control Panel and Control module

When A/C is first turned on it has a knocking noise and hot air starts blowing.

Any ideas on what is causing this?

Hi vegaschuck, Welcome to 2carpros and TY for the donation

Could be the compressor is on its way out, air in the system,pressure too high,and loose support mount

All of that has been checked.....Are there sensors that operate the vent doors between hot and cold?

Could be a door problem with the air mix/blend/mode, also a vacuum and actuator or the HVAC control module itself-it needs to be open up and investigated.

Does that consist on taking the dashboard apart to get to those panels?

Yes sir-plus it can get complicated its not an easy job to do, been there don't like it-

Is removing the dashboard like on a Thunderbird or is it in pieces?

No its not the same

My air conditioner just started blowing hot air a few days ago. When I went to get my oil changed the guy told me i either needed to change my air filter or he saw some cracks in my belt said i might need that replaced. I just bought a brand new cooling fan system July of 05, and I changed the filter that day. Still hot air. I was told to buy Freon...but Im a female I dont know about any of these things......PLEASE HELP ME!!

Get a a/c recharge hose with a gauge. You can check the freon level and fill it with that,