A/C AND HEAT ON AT SAME TIME.
12-26-2017, 09:15 PM
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A/C AND HEAT ON AT SAME TIME.
Hello, I am brand-new to this great board.
The car'* heat and a/c come on at the same time.
I have a 1996 Buick Park avenue with 3.8 engine. At one point I determined that a blend door was malfunctioning but then discovered that the a/c compressor was running while the heater was on. Cold air was coming out of a few vents while hot air was coming out of other vents.
Of course I could rig a relay in the 12 volt line to the a/c clutch or simply unplug that during the winter but I want to fix whatever is causing this fault. Can anyone help?
I sure wish that I had a schematic or a book .
Thank you.
Ros
The car'* heat and a/c come on at the same time.
I have a 1996 Buick Park avenue with 3.8 engine. At one point I determined that a blend door was malfunctioning but then discovered that the a/c compressor was running while the heater was on. Cold air was coming out of a few vents while hot air was coming out of other vents.
Of course I could rig a relay in the 12 volt line to the a/c clutch or simply unplug that during the winter but I want to fix whatever is causing this fault. Can anyone help?
I sure wish that I had a schematic or a book .
Thank you.
Ros
12-26-2017, 09:39 PM
#2
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I don't have schematics for '96 unfortunately.
Do you have dual zone climate control, with the buttons on the passenger side? How cold was it outside when you noticed this? Was the car up to operating temperature yet?
Do you have dual zone climate control, with the buttons on the passenger side? How cold was it outside when you noticed this? Was the car up to operating temperature yet?
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12-26-2017, 10:19 PM
#3
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It'* possible the compressor can run, if you are in the Defrost or Defrost/Heater position....the compressor should not run if the ambient air is below 40F.....
Rjolly asked if you have the auto dual temp system or the manual system? The dual has two temp actuators while the manual has only one...
Rjolly asked if you have the auto dual temp system or the manual system? The dual has two temp actuators while the manual has only one...
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CathedralCub (01-03-2018),
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12-26-2017, 11:47 PM
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Hi, and thanks for the reply.
No, there are not dual controls and the temperatures have been all over the map so, that isn't it.
Ros
No, there are not dual controls and the temperatures have been all over the map so, that isn't it.
Ros
12-26-2017, 11:58 PM
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Thanks for your reply, as well.
Yes, I know that the compressor can run when defrosting so as to supply cold DRY air in order to evaporate the condensed moisture.
There has to be some sensors that feed signals to the bcm or some such and, in turn would activate the a/c or heater.
Thank you.
Ros
Yes, I know that the compressor can run when defrosting so as to supply cold DRY air in order to evaporate the condensed moisture.
There has to be some sensors that feed signals to the bcm or some such and, in turn would activate the a/c or heater.
Thank you.
Ros
It'* possible the compressor can run, if you are in the Defrost or Defrost/Heater position....the compressor should not run if the ambient air is below 40F.....
Rjolly asked if you have the auto dual temp system or the manual system? The dual has two temp actuators while the manual has only one...
Rjolly asked if you have the auto dual temp system or the manual system? The dual has two temp actuators while the manual has only one...
12-27-2017, 12:36 AM
#6
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True Car Nut
Thanks for your reply, as well.
Yes, I know that the compressor can run when defrosting so as to supply cold DRY air in order to evaporate the condensed moisture.
There has to be some sensors that feed signals to the bcm or some such and, in turn would activate the a/c or heater.
Thank you.
Ros
Yes, I know that the compressor can run when defrosting so as to supply cold DRY air in order to evaporate the condensed moisture.
There has to be some sensors that feed signals to the bcm or some such and, in turn would activate the a/c or heater.
Thank you.
Ros
Straight from the manual:
http://www.vadengmpp.com/owners-manu...ParkAvenue.pdf
The buttons on your system allow you to choose settings
to deliver air through lower, middle or windshield outlets.
RECIRC: Press this button to limit the amount of air or
cool the air in your vehicle. To turn off RECIRC, press
the button again. If you select FRONT defrost or
BLEND while RECIRC is selected, the system will
automatically turn off RECIRC to prevent fogging.
VENT This setting directs airflow through the middle
instrument panel outlets. The air conditioning
compressor is not working when VENT is selected.
HTR: This button directs air out of the heater outlets.
Most of the air will come from the floor outlets while
some of it will flow through the windshield and side
window outlets. The air conditioning compressor is not
working when HTR is selected.
BLEND: When BLEND is selected the airflow will be
split between the windshield and the floor outlets. The
air conditioning compressor will be operating.
FRONT This setting directs most of the airflow toward
the windshield.
OFF: The ventilation system always allows fresh air to
flow through your Buick when the vehicle is moving.
The system will try to keep the air at a previously
chosen temperature. When the system is off, the blower
fan is also off.
MAX: This setting directs airflow through the middle
instrument panel outlets.
NORM: This setting cools the air entering your vehicle
and directs it through the middle instrument panel outlets.
BI-LEV: This setting directs warm air to the floor and
cooler air to the middle instrument panel outlet
to deliver air through lower, middle or windshield outlets.
RECIRC: Press this button to limit the amount of air or
cool the air in your vehicle. To turn off RECIRC, press
the button again. If you select FRONT defrost or
BLEND while RECIRC is selected, the system will
automatically turn off RECIRC to prevent fogging.
VENT This setting directs airflow through the middle
instrument panel outlets. The air conditioning
compressor is not working when VENT is selected.
HTR: This button directs air out of the heater outlets.
Most of the air will come from the floor outlets while
some of it will flow through the windshield and side
window outlets. The air conditioning compressor is not
working when HTR is selected.
BLEND: When BLEND is selected the airflow will be
split between the windshield and the floor outlets. The
air conditioning compressor will be operating.
FRONT This setting directs most of the airflow toward
the windshield.
OFF: The ventilation system always allows fresh air to
flow through your Buick when the vehicle is moving.
The system will try to keep the air at a previously
chosen temperature. When the system is off, the blower
fan is also off.
MAX: This setting directs airflow through the middle
instrument panel outlets.
NORM: This setting cools the air entering your vehicle
and directs it through the middle instrument panel outlets.
BI-LEV: This setting directs warm air to the floor and
cooler air to the middle instrument panel outlet
In the dash, all air is pulled through the A/C Evaporator core, and then the blend door (moved by the airmix actuator) controls how much of that air is then pushed through the heater core before it goes out to the selected vents. If the A/C system is not properly charged, it can cause a difference in how cold air is from one side to the other. If the heater core is plugged up, it can cause a similar effect for heat.
Check to make sure the airmix actuator has full range of motion and moves freely, as that is generally the biggest problem child. Then, check the heater core pipes to make sure there is not a difference in temperature from one side to the other, indicating a plugged up unit.
Of course, I say this, and I forgot to mention that air trapped in the cooling system (or low coolant) can also wreak this kind of havoc as well, and these cars are VERY good at trapping air in the cooling system, especially if there is a leak, external, or worse, internal.
The following 2 users liked this post by rjolly87:
CathedralCub (01-03-2018),
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12-27-2017, 12:39 AM
#7
Senior Member
True Car Nut
I know my 97 PA Blend doors are electronic & if temp set to warm, & cold air is coming out of 2, those blend door actuators are probably shot/ they are replaceable.
I had to do many of mine.
My AC will not turn on if it is below 38-40F as to protect system freezing.
If set to vent mode the AC clutch should not engage. When set to defrost it should engage, if it is above 38F-40F.
Factory service manuals for your 96 may be available at Library, but often GM dealers will help with either a manual to view or even parts diagram from fiche.
I had to do many of mine.
My AC will not turn on if it is below 38-40F as to protect system freezing.
If set to vent mode the AC clutch should not engage. When set to defrost it should engage, if it is above 38F-40F.
Factory service manuals for your 96 may be available at Library, but often GM dealers will help with either a manual to view or even parts diagram from fiche.
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1997 Buick Pk Ave (Soft Ride) Suspension!
1997 Buick Pk Ave (Soft Ride) Suspension!
12-27-2017, 06:29 AM
#8
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Certified Car Nut
Microfiche? I haven't seen anyone use microfiche in about 20 years.
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12-27-2017, 11:51 AM
#9
Senior Member
True Car Nut
Ya LOL..Digital fiche..IDK what their new computerized parts schematics is called..
I'll have to ask next time i'm at the dealer..
I'll have to ask next time i'm at the dealer..
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1997 Buick Pk Ave (Soft Ride) Suspension!
1997 Buick Pk Ave (Soft Ride) Suspension!
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