Weird A/C problem...
Thread Starter
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Tuned
Joined: Jan 2006
Posts: 293
Likes: 1
Weird A/C problem...
The A/C functions correctly (although not as cold as I think it should be) for about 1/2 to 3/4 of an hour then the vents gradually close off and air stops blowing from the dash. The fan still blows hard but no air comes out. Any ideas?
Thread Starter
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Tuned
Joined: Jan 2006
Posts: 293
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Tried that...no luck. Although that is almost how it seems, it just gradually quits blowing like the evaporator was freezing up. Are there any other reasons the evaporator would freeze? Water pours out the drains on both front and back and the rear blows fine although it isn't as cold as it should be either. I have a new condensor, dryer, compressor, orifice tube and engine fan. Spent a lot of money in this AC system over the last year and it doesn't work any better than when I started and in this instance it works worse.
Fleet Mechanic
Joined: Aug 2010
Posts: 1,455
Likes: 155
From: Sedalia, CO
Does the air shift from coming out of the dash vents to coming out of the defroster vents, or does it just disappear into, well, the air? If the former, LivinLarge is right about the vacuum leak, so you'll want to figure that out.
Mark
Mark
Elder User
Joined: Apr 2011
Posts: 627
Likes: 4
From: Orange County, CA
Good luck and let us know how it turns out for you.
Karl
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Hotshot
Joined: Jan 2004
Posts: 19,760
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From: St Louis
It is necessary to properly distinguish between "Airflow goes to defrost" or "Airflow gradually stops".
The first is a vacuum leak problem, the second is an iced evaporator. The first will usually resolve itself as soon as manifold vacuum returns to normal, the second will only resolve after the ice melts. If you look under a parked vehicle that the evaporator was iced up in, you'll end up with a very large puddle of water as it melts.
Iced evaporators are usually caused by a stuck cycling switch in CCOT systems.
The first is a vacuum leak problem, the second is an iced evaporator. The first will usually resolve itself as soon as manifold vacuum returns to normal, the second will only resolve after the ice melts. If you look under a parked vehicle that the evaporator was iced up in, you'll end up with a very large puddle of water as it melts.
Iced evaporators are usually caused by a stuck cycling switch in CCOT systems.
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Thread Starter
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Tuned
Joined: Jan 2006
Posts: 293
Likes: 1
It gradually just disappears. I hear the fan blowing but no air comes out anywhere.
Thread Starter
|
Tuned
Joined: Jan 2006
Posts: 293
Likes: 1
It is necessary to properly distinguish between "Airflow goes to defrost" or "Airflow gradually stops".
The first is a vacuum leak problem, the second is an iced evaporator. The first will usually resolve itself as soon as manifold vacuum returns to normal, the second will only resolve after the ice melts. If you look under a parked vehicle that the evaporator was iced up in, you'll end up with a very large puddle of water as it melts.
Iced evaporators are usually caused by a stuck cycling switch in CCOT systems.
The first is a vacuum leak problem, the second is an iced evaporator. The first will usually resolve itself as soon as manifold vacuum returns to normal, the second will only resolve after the ice melts. If you look under a parked vehicle that the evaporator was iced up in, you'll end up with a very large puddle of water as it melts.
Iced evaporators are usually caused by a stuck cycling switch in CCOT systems.
Hotshot
Joined: Jan 2004
Posts: 19,760
Likes: 1,079
From: St Louis
The pressure cycling switch is usually screwed into the accumulator or into the low pressure line at the accumulator.
It can be replaced without loosing refrigerant as there is a Shrader valve under it.
It can be replaced without loosing refrigerant as there is a Shrader valve under it.
Senior User
Joined: Nov 2005
Posts: 307
Likes: 0
From: central texas
a lot of vehicles have the thermo sensor in a location that allows the evaporator to over cool, thus freezing up in high humid conditions… moving the sensor can sometimes rectify the situation. there should be a service bulletin on the issue..
the easiest fix, use the air recirc feature..
the easiest fix, use the air recirc feature..
Elder User
Joined: Jan 2013
Posts: 916
Likes: 1
From: Reno, NV
Ramsay - are you sure there is no air coming out of the defroster? You say you hear but don't feel it. I only ask because I ran into this yesterday and after reading posts on here I'm 99% sure it's the vacuum leak problem.
Does your truck have the automatic temp controls or is it the *****?
Does your truck have the automatic temp controls or is it the *****?