2003 ford mustang cold air coming from defrost

Make sure radiator is full of coolant, this system heats the vehicle, also if you can smell coolant it may be a bad or leaking heater core? Hope this helps?

you may have it on the defrost setting

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most fords were built to whenever the air is on to blow air onto the windows as well. most people dont notice it cause its only a partial air. if it is blowing out pretty hard then the most likely cause of that is that the little flap in your air ducting is stuck or the return spring on it has gone bad. hope i helped, good luck with the fix.

possibly you a/c request button is broken. jump the connector to test.

Check the vaccum line at the vacuum distribution block (to the right of the brake master cylinder). It's the smallest vacuum hose.

Does it still blow out the floor and defrost when you set the switch to those positions or does it alway blow out the defrost no matter what? If you can get air to blow out to the floor, then it sounds like you lost the switch that controls the airflow to the vents. If it only blows out the defrost, then you probably lost the vacuum to all of the switches. When the vacuum is lost, it will only blow out the defrost. Check the smallest line on the vacuum distribution block located in the corner near the brake master cyclinder. That line provides the vacuum to control the direction of airflow within the cabin.

most fords control the vents with vacuum and if it looses vacuum the default mode is defrost. so check the source coming from the motor(sometimes its a electric pump but i think it will be feed form the motor for you) it will most likely go through the fire wall on the passengers side also there should be a resivour under the dash some where. you will just have to find the vacuum supply line and locate the leak.

the switch is protected by a fuse and it activates the relay which handles the high current needed to operaate the back window. You should have a light that comes on when the switch is turned on.

it's behind dash panel, center.

You probably have a vacuum leak on the passenger side. its a small plastic hose some times they come unpluged from the engine. or brake.