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Discussion Starter #1
2005 Cadillac Deville. The driver side temperature with AC on is 80 degrees, while the passenger side is 40 degrees on re-circulation. Before the driver side would get cool after a while of driving, but recently it hasn't, it stays at around 80 degrees constantly. I took the driver side blend door actuator off so that I could control the temperature by hand. I turned the knob that the actuator controlled to the hot position and then to the cold position to test it. When I turned it to the cold position by hand, it only got to 80 degrees, so it is not the actuator that is causing this. I checked the Freon level and it was perfect, but after doing some research, I decided to release some Freon from the car, nothing happened, then I overfilled the car with Freon, nothing happened again. If anyone has some advice, it would be much appreciated. Thank you
 

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2000 Deville Base, 2019 Corvette Grand Sport
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Well if your freon is good as is your actuator don't know what to say. Those are the two things that cause your problem. Did you pull codes to be safe? BTW how did you check freon level? Perfect fill is 2.2lbs or 35.2 ozs.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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19,658 Posts
2005 Cadillac Deville. The driver side temperature with AC on is 80 degrees, while the passenger side is 40 degrees on re-circulation. Before the driver side would get cool after a while of driving, but recently it hasn't, it stays at around 80 degrees constantly. I took the driver side blend door actuator off so that I could control the temperature by hand. I turned the knob that the actuator controlled to the hot position and then to the cold position to test it. When I turned it to the cold position by hand, it only got to 80 degrees, so it is not the actuator that is causing this. I checked the Freon level and it was perfect, but after doing some research, I decided to release some Freon from the car, nothing happened, then I overfilled the car with Freon, nothing happened again. If anyone has some advice, it would be much appreciated. Thank you
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I took the driver side blend door actuator off so that I could control the temperature by hand. I turned the knob that the actuator controlled to the hot position and then to the cold position to test it. When I turned it to the cold position by hand, it only got to 80 degrees
can't be -

the MIX door actuator controls a plastic door that allows or prevents cabin air
from passing through the AC evaporator core -
there is one for the driver side and one for the passenger side -

there is only one evaporator core - shared by both driver side and passenger side -
SO - it is simply not possible to get 40* from the passenger vents and 80* from the driver vents
IF you manually moved the driver side mix door to the full cold position -
 

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2003 Deville Base
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Welcome to the forums! You'll get plenty of advice from dedicated gear heads but you need to be prepared for blunt answers. I"m with Ron93, how did you check the level? How did you release refrigerant? and why in the world would you over fill it? Sounds like time to take it to a professional tech.
 

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Discussion Starter #5
I measured the level using a 134 gun that had a gauge on it which I got a discount auto part store. I read online that low refrigerant could cause temperature disparities, and even though the gun said it was at the good level, I thought it was worth a shot, so I put more in.

The codes I have are:
C1295 - Brake Lamp Switch Circuit Open - History
B0409 CADILLAC - Temperature Control 1 Circuit Range - Current
B0408 CADILLAC - Front Temperature Control Circuit - Current - Went away once I plugged the actuator back in

If it makes a difference, I had to replace the passenger side blend door actuator using an off brand part a few months ago due to a similar issue, which is fixed now.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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19,658 Posts
I measured the level using a 134 gun that had a gauge on it which I got a discount auto part store. I read online that low refrigerant could cause temperature disparities, and even though the gun said it was at the good level, I thought it was worth a shot, so I put more in.

The codes I have are:
C1295 - Brake Lamp Switch Circuit Open - History
B0409 CADILLAC - Temperature Control 1 Circuit Range - Current
B0408 CADILLAC - Front Temperature Control Circuit - Current - Went away once I plugged the actuator back in

If it makes a difference, I had to replace the passenger side blend door actuator using an off brand part a few months ago due to a similar issue, which is fixed now.
=======================
I read online that low refrigerant could cause temperature disparities,
this is PARTIALLY true -
you might notice a SMALL difference between passenger side and driver side discharge air temps
with a SLIGHTLY low freon charge -

cold - liquid freon flows through the evaporator core -
the air distribution system has TWO zones - passenger side and driver side -
the passenger side air flows through the first half of the evaporator core where the freon flows in -
the driver side air flows through the other half of the evaporator core - where the freon exits -

with a properly charged system - the entire evaporator core has liquid freon flowing through it -
the cold liquid freon picks up cabin heat - and actually boils and turns to gas - AFTER it exits the evaporator core -

with a SLIGHTLY low system -
the freon can start to boil - and turn to gas - while still inside the evaporator core -
freon in a gaseous state can not pick up as much heat as liquid freon -
the result is WARMER discharge air from the driver side vents -

what you describe is cold air from the passenger side vents and HOT air from the driver side

the MIX DOORS move to direct airflow between the evaporator core for COLD -
and heater core for HEAT - or somewhere between -

the passenger side mix door sounds like it is operating properly -
but the driver side mix door is malfunctioning -
AND - you have a code B0409 - Air Mix Door #1 Range Error -
 

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Discussion Starter #7
=======================
I read online that low refrigerant could cause temperature disparities,
this is PARTIALLY true -
you might notice a SMALL difference between passenger side and driver side discharge air temps
with a SLIGHTLY low freon charge -

cold - liquid freon flows through the evaporator core -
the air distribution system has TWO zones - passenger side and driver side -
the passenger side air flows through the first half of the evaporator core where the freon flows in -
the driver side air flows through the other half of the evaporator core - where the freon exits -

with a properly charged system - the entire evaporator core has liquid freon flowing through it -
the cold liquid freon picks up cabin heat - and actually boils and turns to gas - AFTER it exits the evaporator core -

with a SLIGHTLY low system -
the freon can start to boil - and turn to gas - while still inside the evaporator core -
freon in a gaseous state can not pick up as much heat as liquid freon -
the result is WARMER discharge air from the driver side vents -

what you describe is cold air from the passenger side vents and HOT air from the driver side

the MIX DOORS move to direct airflow between the evaporator core for COLD -
and heater core for HEAT - or somewhere between -

the passenger side mix door sounds like it is operating properly -
but the driver side mix door is malfunctioning -
AND - you have a code B0409 - Air Mix Door #1 Range Error -
Thanks that really helped and explained a lot. Is there a way to fix the mix blend door that does not involve tearing up the whole dash? Seems expensive!
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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19,658 Posts
Thanks that really helped and explained a lot. Is there a way to fix the mix blend door that does not involve tearing up the whole dash? Seems expensive!
========================
I have never heard of the mix door itself being the problem -

the mix door actuator can be replaced from under the dash
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
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19,658 Posts
That happened to me and I put more refrigerant, on the high side of green on the meter.
=====================
IF adding freon solved your problem -
your system WAS low on freon - meaning you DO have a leak - somewhere -

and with that mickeymouse color wheel gauge -
you have no idea how much freon is in the system -
it MIGHT be overcharged - or it MIGHT still be undercharged -
 

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2000 Deville Base, 2019 Corvette Grand Sport
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=====================
IF adding freon solved your problem -
your system WAS low on freon - meaning you DO have a leak - somewhere -

and with that mickeymouse color wheel gauge -
you have no idea how much freon is in the system -
it MIGHT be overcharged - or it MIGHT still be undercharged -
Just curious, can being undercharged harm the system? I know mine is undercharged because it was bone empty and I put in two cans (24oz) and it got nice and cold and it stayed that way so I left it as is to be safe.
 

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Master of the Dark Art of Diagnostics
2003 DHS - two-2002 DHS, 2003 SLS, 1995 Sedan DeVille, 1989 Coupe DeVille
Joined
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19,658 Posts
Just curious, can being undercharged harm the system? I know mine is undercharged because it was bone empty and I put in two cans (24oz) and it got nice and cold and it stayed that way so I left it as is to be safe.
====================
can being undercharged harm the system?
YES - for a couple different reasons -

freon carries the oil that lubes the compressor pistons -
low freon means LESS oil getting to the compressor -

the other MAJOR concern is the compressor "short cycling" -

there is a LOW pressure switch in the system -
if the freon is undercharged - the LOW (suction) side pressure can get TOO low -
the low-pressure switch will disable the compressor -
as the "static" pressure rises above the "minimum" low pressure -
the compressor re-engages - runs for a short time - and dis-engages again -
this constant short cycling WILL wear out the compressor clutch -
AND the AC won't get as cold as it could -

OVER-PRESSURE can also cause short-cycling - but for the opposite reason -
the HIGH (discharge) side pressure can get too high -
the high-pressure switch will disable the compressor -
as the "static" pressure drops below the "maximum" high pressure -
the compressor re-engages - runs for a short time - and dis-engages again -
this constant short cycling WILL wear out the compressor clutch -
AND the AC won't get as cold as it could -
 

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2001 Deville base
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31 Posts
=====================
IF adding freon solved your problem -
your system WAS low on freon - meaning you DO have a leak - somewhere -

and with that mickeymouse color wheel gauge -
you have no idea how much freon is in the system -
it MIGHT be overcharged - or it MIGHT still be undercharged -
Thanks. There was one hose that was leaking. The accumulator was also leaking. I found the leaks by using the UV dye. Then I vacuumed the system and recharged it. All was well. The extra refrigerant was just a quick semi-fix until I had the time the replace the items leaking. I did use the gauge to recharge the system properly.
 
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