A/C blows hot air

Tiny
GIANT63
  • MEMBER
  • 2001 MERCURY SABLE
Six cylinder front wheel drive automatic 83,500 miles.

My car has ATC. The air conditioner blows hot air. When I set the temperature control it will not switch to the lower temperature from the heat control. When a certain temperature is reached it usually switches to maintain a temperature.
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Thursday, June 3rd, 2010 AT 8:58 PM

21 Replies

Tiny
MERLIN2021
  • EXPERT
Let me get a clarification please, your controls are digital, and the numbers do not change when lowering to the desired temperature? Or the digital readout lowers, but the A/C blows hot?

This sounds like a temperature blend door actuator that is not working.

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

Run the self diagnostic test on it by turning the key to on, then press off and floor at the same time, then within two seconds, press auto, If there is a problem a trouble code will appear on the display. To exit self test, press the blue, cooler button this also retains error codes, To erase codes and exit, press defrost, choose one of these before you power down the system. Test with engine at 120 degrees or more, and cabin between 40 to 90 degrees. Post any codes recorded here and I let you know what is defective.

Here are the wiring diagrams for the air conditioner so you can see how the system works.

There are 6 fuses that run the system lets start by checking them by using the wiring diagram to show you the fuse numbers below.

https://www.2carpros.com/articles/how-to-check-a-car-fuse

Check out the diagrams (below).

Please let us know what you find. We are interested to see what it is.

Cheers
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+8
Friday, June 4th, 2010 AT 5:58 PM
Tiny
GIANT63
  • MEMBER
I ran the test and I did not get any codes. All it gave me was three straight lines. I checked after I ran the test by putting the A/C on and the clutch engages on the compressor but still get hot air.
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Sunday, June 6th, 2010 AT 2:10 PM
Tiny
MERLIN2021
  • EXPERT
My guess would be the blend door, but the lines should be rotating as it performs a system test, then it should report codes, or 888 for pass. The test does take a few minutes, did you wait?
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Monday, June 7th, 2010 AT 6:59 PM
Tiny
GIANT63
  • MEMBER
I took a chance and replaced the temperature blend door motor and it worked! I am so happy thanks for you help. I cannot believe this site is free! God bless you guys.
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-1
Tuesday, June 8th, 2010 AT 3:41 AM
Tiny
MERLIN2021
  • EXPERT
Glad you could get it fixed, that kind of problem can be tough. Please use 2CarPros anytime we are here to help.

Cheers
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Saturday, June 12th, 2010 AT 9:02 AM
Tiny
JJSABLE2001
  • MEMBER
  • 2001 MERCURY SABLE
  • 6 CYL
  • 2WD
  • AUTOMATIC
  • 83,000 MILES
AC was working fine a couple of days ago. It got cold so I used the heater. Now it is warm again I tried to turn on AC but it still blows very, very hot. The heater is stuck. When I press the AC button I hear the compressor kick in. Help it is 90 degrees outside.
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Thursday, March 15th, 2018 AT 3:19 PM (Merged)
Tiny
RENAUDTN
  • MEMBER
Blend door failure is a pretty common problem on this car. I would get it checked out.
Either the blend door or the blend door actuator.
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Thursday, March 15th, 2018 AT 3:19 PM (Merged)
Tiny
RIWAHU
  • MEMBER
  • 2001 MERCURY SABLE
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 130,000 MILES
Yesterday, we had streets flooded and I drove through water that was probably deeper than what I should have gone through. This morning, when I started the car, the A/C was blowing hot. The compressor is running and the evaporator is collecting moisture on the outside, so something is either stopped up, shorted out, or keeping a flap from opening or closing. I do not think there are vacuum lines, but I could be wrong. Could it be a sensor? Thanks! P.S. I has been working fine until today; no leaks, noises, etc.
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Thursday, March 15th, 2018 AT 3:19 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
Is the magnetic clutch engaging the compressor when you turn AC on?
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Thursday, March 15th, 2018 AT 3:19 PM (Merged)
Tiny
BOWKILL2
  • MEMBER
  • 2002 MERCURY SABLE
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 78,000 MILES
My A/C only puts out real hot air, no matter what temperature is set it to. One mechanic told me it was overcharged, then another just told me it was a motor on the inside that turns a door from heat to cold. There never were any tests done, they were just telling me what they thought. What do you think?
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Thursday, March 15th, 2018 AT 3:20 PM (Merged)
Tiny
RASMATAZ
  • MEMBER
Check the high and low pressures this will determine if it needs Freon. Could be the clutch, pressure switch and the air blend door stuck in the heat position.
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Thursday, March 15th, 2018 AT 3:20 PM (Merged)
Tiny
OSLO
  • MEMBER
  • 2002 MERCURY SABLE
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 95,000 MILES
Why would the air conditioning be blowing hot air?
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Thursday, March 15th, 2018 AT 3:20 PM (Merged)
Tiny
BMRFIXIT
  • EXPERT
It may be low on Freon.
Have it checked or add 134A.
Check if clutch on compressor is working.
Check fuses and relays.
Good luck.
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Thursday, March 15th, 2018 AT 3:20 PM (Merged)
Tiny
MERLIN2021
  • EXPERT
I do not know what type of gauge you are using, but maybe the one built into a can of R-134a? Get a normal set of manifold gauges, and go from there, the A/C compressor cycles too much because it is low on R-134a. Charge with A/C set in normal A/C mode, not max!
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Thursday, March 15th, 2018 AT 3:20 PM (Merged)
Tiny
ANGEL_GIRL
  • MEMBER
  • 1997 MERCURY SABLE
Six cylinder front wheel drive automatic.

Hi, my air condition has started acting up right when I need it the most.
We thought it was low on coolant so we bought some and guess what not the problem. Well, here is what it is doing. I noticed when I turned it on the other day at first nothing but hot air. When I started driving it started cooling down. It does this periodically. It will be cool for a little bit then hot. When you turn the air conditioning on the clutch on the air conditioning motor kicks on and off. (Did not know if this is normal or not.) Please help. Thank you,
angel_girl
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Thursday, March 15th, 2018 AT 3:20 PM (Merged)
Tiny
MHPAUTOS
  • EXPERT
Hi there,

The first thing you should do with any A/C problem is get the pressures checked. This will give the Tech a better idea as to what the problem may be. Just adding refrigerant into the system can cause more problems. Get it tested first.

Mark (mhpautos)
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Thursday, March 15th, 2018 AT 3:20 PM (Merged)
Tiny
ELAINE04
  • MEMBER
  • 1999 MERCURY SABLE
  • 120 MILES
I checked AC pressure and that is fine, fan blowing hot air. I do not hear blend door open. How do I fix that?
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Thursday, March 15th, 2018 AT 3:20 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
Behind the dash, center accessed from the bottom and through the glove box.

What are the pressures on the AC?

Roy
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Thursday, March 15th, 2018 AT 3:20 PM (Merged)
Tiny
M_H_RITZEL
  • EXPERT
If it is putting out cold air then hot I would believe there may be a leak someplace. There are dyes you can get at a auto store to help find the leak. Also, it does sound like it is low on Freon.

https://www.2carpros.com/articles/air-conditioner-leak-detection
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Saturday, March 17th, 2018 AT 7:39 AM
Tiny
NOAH04
  • MEMBER
Air Conditioning Problem
2001 Mercury Sable six cylinder front wheel drive automatic.

Hi, a while back my air conditioning started blowing only hot air. When we took it to the garage for an unrelated problem they said they added some Freon and it seemed to work fine. However, after a few weeks the A/C stopped working and it would only blow hot air again. I checked the blend door actuator and it works fine. Could there be a leak, and that is what is causing the A/C to stop blowing cold air? I also ran the self-diagnostic test and got codes 051 and 053.
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Monday, July 23rd, 2018 AT 10:49 AM

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