Warm air blows out of the A/C?

Tiny
LOVE2MUCHTV
  • MEMBER
  • 2010 MERCURY MOUNTAINEER
  • 4.0L
  • 6 CYL
  • 160,000 MILES
Sometimes when idling non cold air comes out of vents with A/C on. Also, during quick accelerations or up larger hills, the air flow from vents dramatically reduced.
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Monday, June 29th, 2020 AT 5:49 PM

23 Replies

Tiny
KASEKENNY1
  • EXPERT
I suspect your system is just low on charge which could be caused by a leak. so we need to check out these guides on how to figure this out.

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

https://www.2carpros.com/articles/air-conditioner-leak-detection

We can start with what the pressures are to confirm this but I suspect we are going to need to put some Freon in it just to bring it up to proper charge.

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

Let me know what questions you have. Thanks
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Monday, June 29th, 2020 AT 6:48 PM
Tiny
BROJHOP@GMAIL.COM
  • MEMBER
  • 2006 MERCURY MOUNTAINEER
  • 4.6L
  • V8
  • 4WD
  • AUTOMATIC
  • 235,000 MILES
Symptoms: A/C has gone in and out over the last week (mostly out). Compressor is not engaging. Refrigerant is full.

Here's what I've done:

I have replaced the low pressure cycling switch.
I have recharged the system.
I have replaced every o-ring that I can get to.

Here's what I've tested:

I powered the compressor with a small 12v battery. Compressor worked fine and allowed me to recharge the system correctly.
I've tested the low pressure cycling switch for continuity past the connector. Switch and connector are fine. I do not get 12v on this wire when I turn on the A/C.
I've tested the high pressure sensor. Reference (5v), signal (1.3v), ground (good). Voltages are static when A/C is on or off.
The fuses and relay are fine.
I do not know how to test the climate control unit.

How would you proceed?
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Friday, July 17th, 2020 AT 12:26 PM (Merged)
Tiny
KASEKENNY1
  • EXPERT
We need to start with checking pressures. This is the first thing we need to do and cannot assume it is full of Freon because there is no way to tell without knowing the pressures. Just because the system won't take any more Freon does not mean it is full.

If you don't have a gauge set to get high and low side pressures then check with local parts stores to see if they have tool rental programs. Then hook up the gauges to the low and high side with the engine on and A/C running. Once we get the pressure we will know what action to take.

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

Thanks
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Friday, July 17th, 2020 AT 12:26 PM (Merged)
Tiny
ASEMASTER6371
  • EXPERT
Good morning,

Let us start with the pressures.

Can you give me the high and low side pressures both with the A/C off and running?

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Roy
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Friday, July 17th, 2020 AT 12:26 PM (Merged)
Tiny
SMANDRY
  • MEMBER
  • 2006 MERCURY MOUNTAINEER
Air Conditioning problem
2006 Mercury Mountaineer V8 Two Wheel Drive Automatic

The rear AC only blows warm or hot air, while the front AC blows cold. Neither refrigerant line to the rear evaporator is cold, or hot. Pressure readings on the system are normal and steady.
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Friday, July 17th, 2020 AT 12:26 PM (Merged)
Tiny
DOCFIXIT
  • EXPERT
Hi
Maybe expansion valve stuck open not droping pressure to cool evaporator. see figure


https://www.2carpros.com/forum/automotive_pictures/198357_Graphic_128.jpg


Hope this helps
Thanks for donate
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Friday, July 17th, 2020 AT 12:26 PM (Merged)
Tiny
SMANDRY
  • MEMBER
Thanks for the response. In your picture, is this valve mounted on the side of the evaporator inside the left rear quarter panel, or is it inside the connection block underneath the left-rear corner of the car?
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Friday, July 17th, 2020 AT 12:26 PM (Merged)
Tiny
DOCFIXIT
  • EXPERT
It will be in line to Evap very close to core
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-1
Friday, July 17th, 2020 AT 12:26 PM (Merged)
Tiny
P38JER
  • MEMBER
  • 2003 MERCURY MOUNTAINEER
  • 78,500 MILES
The AC started blowing hot air about 2 weeks ago (i noticed the compressor didn't "click" when the engine is started. So I turned the AC off for approx. 2 days & then I just happened to turn it back on & it blew COLD air. Then 2 days later it went back to blowing hot air. So, I repeated the same scenario & after 2 days, I turned the AC back on & it blew COLD air for 6 days. But, today it went back to blowing hot air again ! I checked the pressure to see if I needed to add refrigerant but the guage said the pressure was in the "Red - Warning" range (approx. 110 !). Any idea why the AC compressor keeps kicking in & out like this? Thanks.
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Friday, July 17th, 2020 AT 12:26 PM (Merged)
Tiny
KEN
  • ADMIN
Hello,

This is one of two things either the system was not running when you installed your gauges and the system is low or the the system has running and the system is overcharged.

Here are two guides that will help you get the problem fixed.

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

and

https://www.2carpros.com/articles/re-charge-an-air-conditioner-system

and

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Please let us know what happens.

Cheers, Ken

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Friday, July 17th, 2020 AT 12:26 PM (Merged)
Tiny
XODENNAXO
  • MEMBER
  • 2003 MERCURY MOUNTAINEER
  • 4.6L
  • V6
  • 4WD
  • AUTOMATIC
  • 197,000 MILES
I have heat when I have it on face or floor but no hot air when I put it on defrost and the rear ceiling vents don t blow hot air either.
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Friday, July 17th, 2020 AT 12:26 PM (Merged)
Tiny
KEN
  • ADMIN
Hello,

It sounds like you have a mode and temperature actuator out which is common. here is a guide to help walk you through the repair with diagrams below to show you the location of the actuator in your car:

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

Check out the diagrams (below). Please let us know what happens.
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Friday, July 17th, 2020 AT 12:26 PM (Merged)
Tiny
ROGERLEE2000
  • MEMBER
  • 2002 MERCURY MOUNTAINEER
  • 6 CYL
  • 130 MILES
I have a 2002 Mercury Mountaineer and my cigarette lighters (ac power not actually using the lighter just chargers etc.) Have not worked since I purchased the car. I have checked the fuse that was listed in the owners manual to be the fuse for them and it is a good fuse. What else may be the problem?
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Friday, July 17th, 2020 AT 12:27 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
If the fuse is good, check to see if there is power to the back of the outlet.

Let me know what you find.
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Friday, July 17th, 2020 AT 12:27 PM (Merged)
Tiny
ROGERLEE2000
  • MEMBER
I took apart what I could to get to the back of the outlets and all (2) of my outlets have power connected to the back of them but I found this wire in the front of my center console that has a plug on it but is not connected to anything. See attached photos to view the plug.
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Friday, July 17th, 2020 AT 12:27 PM (Merged)
Tiny
ROGERLEE2000
  • MEMBER
I also meant to say that the outlets have a wire plugged into them I am not sure if that wire is actually hot or not that is what I was wondering about this plug
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Friday, July 17th, 2020 AT 12:27 PM (Merged)
Tiny
JACOBANDNICKOLAS
  • EXPERT
Do either of the other wires provide power? A 3rd wire could be the jumper to anohter outlet.
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Friday, July 17th, 2020 AT 12:27 PM (Merged)
Tiny
TIMMYJR904
  • MEMBER
  • 2004 MERCURY MOUNTAINEER
  • 4.6L
  • V8
  • AWD
  • AUTOMATIC
  • 22,000 MILES
A/C is turning on and off repeatedly
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Friday, July 17th, 2020 AT 12:27 PM (Merged)
Tiny
CARADIODOC
  • EXPERT
That is the classic symptom of a system that's low on refrigerant. There could be a leak, but at this age, the system likely just needs to be leak-checked, then recharged.
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Friday, July 17th, 2020 AT 12:27 PM (Merged)
Tiny
JRUFF70@GMAIL.COM
  • MEMBER
  • 1999 MERCURY MOUNTAINEER
  • V8
  • AWD
  • AUTOMATIC
  • 145,000 MILES
My AC is not blowing out the vents, it has a new blower motor and AC has been charged.
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Friday, July 17th, 2020 AT 12:27 PM (Merged)

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