'02 Tahoe front AC hot + rear AC cold
May 22nd, 2015, 7:59 PM
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'02 Tahoe front AC hot + rear AC cold
Hey guys,
I have a 2002 Tahoe with automatic AC control in the front (single not dual as in passenger and driver) and a separate rear ac. This has been going on for a while but I've finally reached my boiling point with this. My front AC will sometimes blow hot and sometimes blow decently cold air....but a most of the time warm. My rear AC however blows nothing but ice cold freeze your ***** off cold. I have already checked my cabin air filter and replaced it, my evap and condenser have already been checked for debris which would prevent air flow, I have replaced the head unit or control **** panel in the dashboard for the front in case that had failed, I have replaced the blend door actuator and confirmed that it is moving the door all the way to the cold side, I checked my pressures and refrigerant charge about a year ago and they were fine (even evacuated the system and but it under a vacuum for 2 hours to make sure) but I will check the pressures again after I post this tonight, I have also added an electric cooling fan on the front of the condenser behind the grill (as per the GM TSB #:01-01-39-004A) which tells you to add another fan for more air flow over the condenser, and finally I have just replaced both the high and low pressure switches because a mechanic friend who worked for Chevrolet told me they were having problems with the low pressure switches on the accumulators with the black base and a rubber band around it (P/N 52400312). After all of this, I installed the new switches tonight and still the same thing....**** warm front and ice cold rear.
However after a hissy fit in the driveway, I noticed that the inlet line to the evaporator from the orifice tube up to the firewall was sweating and ice cold but the outlet for the evaporator was not cold at all, it was a normal temp just the same as the temperature as the outside air. Moving down, I found the drier/accumulator was not cold as well; same as the outlet line.
This difference in temperature on the evap lines has my attention. Could this be a clogged evaporator? I have never heard of that before but I wanted to see what others thought of this as well. Or could this possibly be a clogged orifice tube?
I know my compressor is working and there are no leaks, everything electronic is sound and my pressures/refrigerant is good...does anyone have ANY input on this at all? Has anyone seen a clogged evap? Or do these signs point towards the orifice tube? Thank you to anyone who can give me some direction here. This has been going on for too long and I kept putting it off, but this is the month I fix this thing once and for all.
I have a 2002 Tahoe with automatic AC control in the front (single not dual as in passenger and driver) and a separate rear ac. This has been going on for a while but I've finally reached my boiling point with this. My front AC will sometimes blow hot and sometimes blow decently cold air....but a most of the time warm. My rear AC however blows nothing but ice cold freeze your ***** off cold. I have already checked my cabin air filter and replaced it, my evap and condenser have already been checked for debris which would prevent air flow, I have replaced the head unit or control **** panel in the dashboard for the front in case that had failed, I have replaced the blend door actuator and confirmed that it is moving the door all the way to the cold side, I checked my pressures and refrigerant charge about a year ago and they were fine (even evacuated the system and but it under a vacuum for 2 hours to make sure) but I will check the pressures again after I post this tonight, I have also added an electric cooling fan on the front of the condenser behind the grill (as per the GM TSB #:01-01-39-004A) which tells you to add another fan for more air flow over the condenser, and finally I have just replaced both the high and low pressure switches because a mechanic friend who worked for Chevrolet told me they were having problems with the low pressure switches on the accumulators with the black base and a rubber band around it (P/N 52400312). After all of this, I installed the new switches tonight and still the same thing....**** warm front and ice cold rear.
However after a hissy fit in the driveway, I noticed that the inlet line to the evaporator from the orifice tube up to the firewall was sweating and ice cold but the outlet for the evaporator was not cold at all, it was a normal temp just the same as the temperature as the outside air. Moving down, I found the drier/accumulator was not cold as well; same as the outlet line.
This difference in temperature on the evap lines has my attention. Could this be a clogged evaporator? I have never heard of that before but I wanted to see what others thought of this as well. Or could this possibly be a clogged orifice tube?
I know my compressor is working and there are no leaks, everything electronic is sound and my pressures/refrigerant is good...does anyone have ANY input on this at all? Has anyone seen a clogged evap? Or do these signs point towards the orifice tube? Thank you to anyone who can give me some direction here. This has been going on for too long and I kept putting it off, but this is the month I fix this thing once and for all.
May 26th, 2015, 12:16 AM
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Check the HEATER hose from the intake manifold to the firewall, I suspect HOT water in the heater core caused from sticking valve. See if both hoses are close to same temperature. Good luck, JMHO.
David
David
August 27th, 2022, 8:43 AM
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I am having exact symptoms
Hey guys,
I have a 2002 Tahoe with automatic AC control in the front (single not dual as in passenger and driver) and a separate rear ac. This has been going on for a while but I've finally reached my boiling point with this. My front AC will sometimes blow hot and sometimes blow decently cold air....but a most of the time warm. My rear AC however blows nothing but ice cold freeze your ***** off cold. I have already checked my cabin air filter and replaced it, my evap and condenser have already been checked for debris which would prevent air flow, I have replaced the head unit or control **** panel in the dashboard for the front in case that had failed, I have replaced the blend door actuator and confirmed that it is moving the door all the way to the cold side, I checked my pressures and refrigerant charge about a year ago and they were fine (even evacuated the system and but it under a vacuum for 2 hours to make sure) but I will check the pressures again after I post this tonight, I have also added an electric cooling fan on the front of the condenser behind the grill (as per the GM TSB #:01-01-39-004A) which tells you to add another fan for more air flow over the condenser, and finally I have just replaced both the high and low pressure switches because a mechanic friend who worked for Chevrolet told me they were having problems with the low pressure switches on the accumulators with the black base and a rubber band around it (P/N 52400312). After all of this, I installed the new switches tonight and still the same thing....**** warm front and ice cold rear.
However after a hissy fit in the driveway, I noticed that the inlet line to the evaporator from the orifice tube up to the firewall was sweating and ice cold but the outlet for the evaporator was not cold at all, it was a normal temp just the same as the temperature as the outside air. Moving down, I found the drier/accumulator was not cold as well; same as the outlet line.
This difference in temperature on the evap lines has my attention. Could this be a clogged evaporator? I have never heard of that before but I wanted to see what others thought of this as well. Or could this possibly be a clogged orifice tube?
I know my compressor is working and there are no leaks, everything electronic is sound and my pressures/refrigerant is good...does anyone have ANY input on this at all? Has anyone seen a clogged evap? Or do these signs point towards the orifice tube? Thank you to anyone who can give me some direction here. This has been going on for too long and I kept putting it off, but this is the month I fix this thing once and for all.
I have a 2002 Tahoe with automatic AC control in the front (single not dual as in passenger and driver) and a separate rear ac. This has been going on for a while but I've finally reached my boiling point with this. My front AC will sometimes blow hot and sometimes blow decently cold air....but a most of the time warm. My rear AC however blows nothing but ice cold freeze your ***** off cold. I have already checked my cabin air filter and replaced it, my evap and condenser have already been checked for debris which would prevent air flow, I have replaced the head unit or control **** panel in the dashboard for the front in case that had failed, I have replaced the blend door actuator and confirmed that it is moving the door all the way to the cold side, I checked my pressures and refrigerant charge about a year ago and they were fine (even evacuated the system and but it under a vacuum for 2 hours to make sure) but I will check the pressures again after I post this tonight, I have also added an electric cooling fan on the front of the condenser behind the grill (as per the GM TSB #:01-01-39-004A) which tells you to add another fan for more air flow over the condenser, and finally I have just replaced both the high and low pressure switches because a mechanic friend who worked for Chevrolet told me they were having problems with the low pressure switches on the accumulators with the black base and a rubber band around it (P/N 52400312). After all of this, I installed the new switches tonight and still the same thing....**** warm front and ice cold rear.
However after a hissy fit in the driveway, I noticed that the inlet line to the evaporator from the orifice tube up to the firewall was sweating and ice cold but the outlet for the evaporator was not cold at all, it was a normal temp just the same as the temperature as the outside air. Moving down, I found the drier/accumulator was not cold as well; same as the outlet line.
This difference in temperature on the evap lines has my attention. Could this be a clogged evaporator? I have never heard of that before but I wanted to see what others thought of this as well. Or could this possibly be a clogged orifice tube?
I know my compressor is working and there are no leaks, everything electronic is sound and my pressures/refrigerant is good...does anyone have ANY input on this at all? Has anyone seen a clogged evap? Or do these signs point towards the orifice tube? Thank you to anyone who can give me some direction here. This has been going on for too long and I kept putting it off, but this is the month I fix this thing once and for all.
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