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Hot ac
1999 Buick Century

Hot AC

(1999 Buick Century)
When I turn on the AC and even after its been running a while I get warm air out of the driver vents and cold air out of the passenger vents. Its a climate control system. Why does it do that I wonder?
1 answer & 1 comment
Popular Answer
on September 30, 2009
There are little doors or flaps inside the dash that control the airflow to the different vents, and the temperature of the airflow. One of these doors may be sticking, or the system that controls the doors is malfunctioning.
I checked and there is a technical service bulletin about a similar problem # 02-02-39-001 I suggest taking this to a dealer and have them check this bulletin and check for others, and diagnose the problem accordingly.
Condition:
Some customers may comment on a temperature variation between the left and right hand ducts. Typical concerns may include that the right side of the vehicle cools down but the left stays warm or the opposite. This condition is sometimes associated by the customer with a recent service visit for other non-related repairs. The codes, DTC B0361 or B0441, may be
present but will not illuminate a telltale lamp.
Cause:
The HVAC controller unit and the TEMP door actuator motors rely on a feedback system that supplies the controller with count values in order to accurately adjust the air temperature. When battery power is interrupted to the HVAC controller, the current actuator position values are lost. When power is restored, the controller will perform a "sweep test" of the doors from full cold to full hot and record the end values for reference. Over time, the TEMP doors may develop some flexing when run to their extremes. This flexing allows the count values to run out of range (beyond 0-255) and results in DTC code B0361 or B0441 to set.
Correction:
A revised HVAC controller has been released with new programming that allows for a wider tolerance
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on October 01, 2009
Thank you. I'll check it out.
General Diagnosis
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on September 30, 2009
There are little doors or flaps inside the dash that control the airflow to the different vents, and the temperature of the airflow. One of these doors may be sticking, or the system that controls the doors is malfunctioning.
I checked and there is a technical service bulletin about a similar problem # 02-02-39-001 I suggest taking this to a dealer and have them check this bulletin and check for others, and diagnose the problem accordingly.
Condition:
Some customers may comment on a temperature variation between the left and right hand ducts. Typical concerns may include that the right side of the vehicle cools down but the left stays warm or the opposite. This condition is sometimes associated by the customer with a recent service visit for other non-related repairs. The codes, DTC B0361 or B0441, may be
present but will not illuminate a telltale lamp.
Cause:
The HVAC controller unit and the TEMP door actuator motors rely on a feedback system that supplies the controller with count values in order to accurately adjust the air temperature. When battery power is interrupted to the HVAC controller, the current actuator position values are lost. When power is restored, the controller will perform a "sweep test" of the doors from full cold to full hot and record the end values for reference. Over time, the TEMP doors may develop some flexing when run to their extremes. This flexing allows the count values to run out of range (beyond 0-255) and results in DTC code B0361 or B0441 to set.
Correction:
A revised HVAC controller has been released with new programming that allows for a wider tolerance
Sign in to reply
on October 01, 2009
Thank you. I'll check it out.

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