Air Conditioning / Heater question [Problems]
Thread Starter
Safety Car
Joined: Mar 2005
Posts: 4,454
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From: The Surgeon General has warned that it's ok to smoke mustangs!
St. Jude Donor '06-'07
Air Conditioning / Heater question [Problems]
Well, the unbelievable happened here in Dallas yesterday! It dropped down to the 20's.
This morning, while sitting in my car waiting for the car to warm up, I notice my heater was acting a little funny. I looked down to make sure my a/c light was on so that I could heat the cabin. It's off, and I'm thinking to myself "I could'a swore I hit the button". Well, I hit the button again, and noticed that the light was blinking for a few seconds and turn off!
I'm not sure what the problem is so I have to do one of these------>
Anyone know what would cause the a/c button light to blink? Anyone experience this before? Anyone know what the fix is?
03' Coupe w/ Dual a/c! (Thank god for heated seats
)
Thanks for your help and
****'s!
This morning, while sitting in my car waiting for the car to warm up, I notice my heater was acting a little funny. I looked down to make sure my a/c light was on so that I could heat the cabin. It's off, and I'm thinking to myself "I could'a swore I hit the button". Well, I hit the button again, and noticed that the light was blinking for a few seconds and turn off!
I'm not sure what the problem is so I have to do one of these------>
Anyone know what would cause the a/c button light to blink? Anyone experience this before? Anyone know what the fix is?
03' Coupe w/ Dual a/c! (Thank god for heated seats
)Thanks for your help and
****'s!
Drifting
Joined: Jun 2006
Posts: 1,444
Likes: 401
From: Palm City
St. Jude Donor '06-'11
Hello. Same thing happen to me. Mine was the PCM. Easy fix. Find one that is pre-programed. It is under the batterie tray. I think that there are some venders on this site that sell them.
Drifting
Joined: May 2000
Posts: 1,917
Likes: 3
From: Southern NH
Before jumping to conclusions that there is a serious problem, PCM or otherwise, this is normal operation for the Dual Zone unit depending on the external temp reading.
If the external temp is reading below ~38F the system will prevent the AC from coming on. When you hit the AC button in this condition, it will blink 3 times then turn off to indicate that the operation is not allowed. Similarly in warmer temps if the system is directing airflow to the defogger windshield vent the AC is automatically ON - if you try to turn the AC off by hitting the AC button it will blink 3 times and stay on.
The question is why are you hitting the AC button to heat? Just hit the AUTO button and set the desire temp.
Also, if the external temp is inaccurate (it's showing much colder on the display than actual temp) then the external temp sensor is reporting an incorrect reading either due to it failing or a corroded connector. The head unit still makes decisions based on that erroneous value and will prevent the AC from kicking in even on a very hot day. By disconnecting the sensor the temp will default to ~ 60F and allow the AC to come on. But as you said it's in the 20s so that's not your problem.
If the external temp is reading below ~38F the system will prevent the AC from coming on. When you hit the AC button in this condition, it will blink 3 times then turn off to indicate that the operation is not allowed. Similarly in warmer temps if the system is directing airflow to the defogger windshield vent the AC is automatically ON - if you try to turn the AC off by hitting the AC button it will blink 3 times and stay on.
The question is why are you hitting the AC button to heat? Just hit the AUTO button and set the desire temp.
Also, if the external temp is inaccurate (it's showing much colder on the display than actual temp) then the external temp sensor is reporting an incorrect reading either due to it failing or a corroded connector. The head unit still makes decisions based on that erroneous value and will prevent the AC from kicking in even on a very hot day. By disconnecting the sensor the temp will default to ~ 60F and allow the AC to come on. But as you said it's in the 20s so that's not your problem.
Instructor
Joined: Jun 2006
Posts: 140
Likes: 0
From: NE Ohio & So Cal
Originally Posted by JC in XTC5
Before jumping to conclusions that there is a serious problem, PCM or otherwise, this is normal operation for the Dual Zone unit depending on the external temp reading.
If the external temp is reading below ~38F the system will prevent the AC from coming on. When you hit the AC button in this condition, it will blink 3 times then turn off to indicate that the operation is not allowed. Similarly in warmer temps if the system is directing airflow to the defogger windshield vent the AC is automatically ON - if you try to turn the AC off by hitting the AC button it will blink 3 times and stay on.
The question is why are you hitting the AC button to heat? Just hit the AUTO button and set the desire temp.
Also, if the external temp is inaccurate (it's showing much colder on the display than actual temp) then the external temp sensor is reporting an incorrect reading either due to it failing or a corroded connector. The head unit still makes decisions based on that erroneous value and will prevent the AC from kicking in even on a very hot day. By disconnecting the sensor the temp will default to ~ 60F and allow the AC to come on. But as you said it's in the 20s so that's not your problem.
If the external temp is reading below ~38F the system will prevent the AC from coming on. When you hit the AC button in this condition, it will blink 3 times then turn off to indicate that the operation is not allowed. Similarly in warmer temps if the system is directing airflow to the defogger windshield vent the AC is automatically ON - if you try to turn the AC off by hitting the AC button it will blink 3 times and stay on.
The question is why are you hitting the AC button to heat? Just hit the AUTO button and set the desire temp.
Also, if the external temp is inaccurate (it's showing much colder on the display than actual temp) then the external temp sensor is reporting an incorrect reading either due to it failing or a corroded connector. The head unit still makes decisions based on that erroneous value and will prevent the AC from kicking in even on a very hot day. By disconnecting the sensor the temp will default to ~ 60F and allow the AC to come on. But as you said it's in the 20s so that's not your problem.
Le Mans Master
Joined: Dec 2001
Posts: 7,788
Likes: 6
From: Winchester TN
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St. Jude Donor '03-'04-'05-'06-'07-'11
Hi Folks -
Just to clarify - yes, the flashing ac light is normal operation, but....
The AC comes on in any defrost/defog mode - regardless of outside temps (at least on my two C5's).
To turn off the ac when it is flashing and staying ON - hit the mode selector twice and then hit the AC button - this should put the little air direction indicators to show the dash or footwell vents active (or both) and will allow you to turn off the ac compressor.
All newer cars have the AC on when the defrost is active - even our 98 lumina does this.
best regards -
mqqn
Just to clarify - yes, the flashing ac light is normal operation, but....
The AC comes on in any defrost/defog mode - regardless of outside temps (at least on my two C5's).
To turn off the ac when it is flashing and staying ON - hit the mode selector twice and then hit the AC button - this should put the little air direction indicators to show the dash or footwell vents active (or both) and will allow you to turn off the ac compressor.
All newer cars have the AC on when the defrost is active - even our 98 lumina does this.
best regards -
mqqn
Drifting
Joined: May 2000
Posts: 1,917
Likes: 3
From: Southern NH
Originally Posted by mqqn
Hi Folks -
Just to clarify - yes, the flashing ac light is normal operation, but....
The AC comes on in any defrost/defog mode - regardless of outside temps (at least on my two C5's).
To turn off the ac when it is flashing and staying ON - hit the mode selector twice and then hit the AC button - this should put the little air direction indicators to show the dash or footwell vents active (or both) and will allow you to turn off the ac compressor.
All newer cars have the AC on when the defrost is active - even our 98 lumina does this.
best regards -
mqqn
Just to clarify - yes, the flashing ac light is normal operation, but....
The AC comes on in any defrost/defog mode - regardless of outside temps (at least on my two C5's).
To turn off the ac when it is flashing and staying ON - hit the mode selector twice and then hit the AC button - this should put the little air direction indicators to show the dash or footwell vents active (or both) and will allow you to turn off the ac compressor.
All newer cars have the AC on when the defrost is active - even our 98 lumina does this.
best regards -
mqqn
2000 Owners Manual, Automatic Electronic Dual Climate Control
System (If Equipped), Page 3-8
A/C: This button turns the air conditioning
compressor off or on under most conditions. The light
on the A/C button will come on when the compressor is
operating in either the automatic or manual mode. The
air conditioning does not operate at temperatures below
approximately 35F to 40D (2C to 4C).
The light on the A/C button will flash if pressed when
air conditioning is not allowed.
This is exactly how mine works.
compressor off or on under most conditions. The light
on the A/C button will come on when the compressor is
operating in either the automatic or manual mode. The
air conditioning does not operate at temperatures below
approximately 35F to 40D (2C to 4C).
The light on the A/C button will flash if pressed when
air conditioning is not allowed.
Le Mans Master
Joined: Dec 2001
Posts: 7,788
Likes: 6
From: Winchester TN
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St. Jude Donor '03-'04-'05-'06-'07-'11
Hi JC in XTC5 -
Are we talking about the same thing here?
Your ac compressor runs when the defroster is on - if you can get your car out in the cold test this for yourself - turn on the front defroster and then try to get the AC light to turn off.
Of course the AC is not going to need to put cool air in the car, since it can only put ~40 degree air out of the vents at best.
There are two functions of the AC - one is to dry the air, the other is to cool - the compressor is still going to run for the drying effect, but you cannot run the AC purposely to cool the cabin when the ambient air temp is lower than what is capable for the AC system -
I was not aware of the feature you point out here - thanks - learn something new everyday - so the AC light can flash when the defrost is on and you attempt to turn the AC off manually, OR, if the outside temps are lower than the system can achieve and you attempt to turn on the AC manually.
best regards -
mqqn
Are we talking about the same thing here?
Your ac compressor runs when the defroster is on - if you can get your car out in the cold test this for yourself - turn on the front defroster and then try to get the AC light to turn off.
Of course the AC is not going to need to put cool air in the car, since it can only put ~40 degree air out of the vents at best.
There are two functions of the AC - one is to dry the air, the other is to cool - the compressor is still going to run for the drying effect, but you cannot run the AC purposely to cool the cabin when the ambient air temp is lower than what is capable for the AC system -
I was not aware of the feature you point out here - thanks - learn something new everyday - so the AC light can flash when the defrost is on and you attempt to turn the AC off manually, OR, if the outside temps are lower than the system can achieve and you attempt to turn on the AC manually.
best regards -
mqqn
Drifting
Joined: May 2000
Posts: 1,917
Likes: 3
From: Southern NH
I think we are talking different things. The question was regarding why the AC light flashed and go off when the outside temp was 20F.
In Auto mode, I agree that the system is designed to control the HVAC components including the AC compressor.
In Auto mode, I agree that the system is designed to control the HVAC components including the AC compressor.
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