air conditioning ?
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air conditioning ?
1997 exp xlt, 260 km. is it possible for the a/c to be stuck on? when we have the control set to the right side of the dial, - a/c off- we still have extremely cold air blowing when we have heat control set to a cooler temp. when we shut veh. off, lots of water dripping under the veh. as it does when we run a/c
Hotshot
Joined: Jul 2005
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there is a vacuum controlled blend door that mixes the hot air from the cab with the cold air from the AC to get the desired temp. i would assume that the door is bloken. see old posts on how to replace it by cutting a hole in the duct behind the glove box.
---now we have to assume the AC is also running or you could not get the cold air. remember that the AC is set to run when in the defrost mode and other positiongs to keep the compressore lubed and keep the air dry in side the cab on wet damp days. that could be why the AC is running.
---now we have to assume the AC is also running or you could not get the cold air. remember that the AC is set to run when in the defrost mode and other positiongs to keep the compressore lubed and keep the air dry in side the cab on wet damp days. that could be why the AC is running.
Elder User
Joined: May 2004
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From: Webster, NY
the blend door on a 97 should not be vacuum controlled, it uses a motor (servo motor if you will) to move the door to the desired position. The vacuum unit is use to move the plenum from defrost to the other air positions. Now, there is a heating bypass valve (which is known to be weak and leak) that is also vacuum controlled. This is used by the system when you select the A/C MAX position on the controls. In this case the heater core is bypassed and only the A/C acts on the air (which is how I managed to get cold air in the summer when my blend door was broken). It could be that this valve is stuck in bypass?
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I don't think the blend door is the cause. The AC seems to be stuck on as referenced by the water dripping outside the vehicle. Could try and disconnect the relay to stop the AC. It's in engine compartment passenger side to the rear of the window wash container. Pull the harness and see if the compressor stops.
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thank you for the replys. i do not think it is a door problem because we can get the air to come out of the various locations, vents etc. i will test to see if the compressor is stuck on. the cold that comes out when we have the control set to the blue side is definately air conditioned even tho the other **** is not in the "a/c on" position. hope this makes sense. thanks again.
Hotshot
Joined: Jul 2005
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my mistake on the blend door, it is of cours an electric motor, not vacuum. if it does break, which is common, then you can not control the temp.--- on your last post, the temp control is set to "cold", but i assume you have the selector **** set to defrost or heat? it is possibly that the air conditioner is on in this position. set the temp **** to the red side and see if that works. when set to the cool side (blue) the AC may be on even tho the second **** is not set to AC.-- look at the compressor clutch, it might be kicking in and out, even in the heat- defrost mode.
Former ******
Joined: Nov 2004
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From: Salt Lake City, Utah
Originally Posted by dsquarewd
thank you for the replys. i do not think it is a door problem because we can get the air to come out of the various locations, vents etc. i will test to see if the compressor is stuck on. the cold that comes out when we have the control set to the blue side is definately air conditioned even tho the other **** is not in the "a/c on" position. hope this makes sense. thanks again.
The A/C is supposed to come on in the defrost positions to ensure the AC cycles in the winter. This keeps the seals from drying out. So the AC should be coming on all year round. The trick is to direct the cold and hot air to where it needs to go. The heater core also heats up all year round, but you should not get any hot air in the summer. These two are mixed in various proportions to get cold, hot or warm air. This mixing is controlled by the blend door, which is in turn controlled by the ****.
Last edited by Bear River; Sep 7, 2007 at 12:12 AM.
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thanks for the info. so should i get a puddle of water even though we have the a/c off? we have not noticed that in the past summer months. we usually only get the puddle when the a/c is in on position.
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Senior User
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Yes, if the compressor is running you could get the puddle/drip if the humidity is high enough to condense on the cold AC parts. The compressor SHOULD run when controls are set to everything except OFF and VENT (1st click counterclockwise from OFF on my 97). If the temp control is set to cold (blue) then the air coming out will be cold. Use the temp control **** to mix the hot/cold air to suit.
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From: Webster, NY
It would seem to me that one of the things to diagnose this would be to confirm if the A/C is actually on or not. Pop the hood and take a look at the compressor, if it is clutched and not turning you know it is not running. If it is engaged and running you have your answer on that. I would put the air selector in one of the modes that does not require the A/C (upper vents only) and then put it on A/C MAX and confirm what the compressor is doing.