Automatic Climate Control - Erratic Operation
Group: CLIMATE CONTROLNumber: 02-97-001
Date: APRIL, 2002
Model: 2002 SONATA, XG300/350
Subject
2002 SONATA AND XG300/350
FULL AUTOMATIC TEMPERATURE
CONTROL DIAGNOSIS
DESCRIPTION:
If the HVAC unit is blowing cold air from the vent ducts when warm air is expected; or the HVAC unit is blowing hot air from the vent ducts when cool/cold air is expected, try this quick diagnostic check.
Check the Aspirator Hose by using a 1" square piece of paper.
1. Set blower speed to # 3.
2. Place 1" square paper over the in-car temperature sensor grille located on the FATC control panel.
NOTE:
THE PAPER SHOULD BE SLICKED TO THE GRILL.
3. Decrease the blower speed. The paper should also stick at blower speed # 2. The paper may fall off at blower speed # 1 and will fall off when the blower is switched off.
4. If the paper does NOT stick, then check the aspirator hose for kinking or being disconnected.
SERVICE PROCEDURE:
Re-route the aspirator hose if it is kinked, and/or properly connect the aspirator hose to the control panel.
1. Remove the center fascia panel and inspect to determine if a kinked or disconnected aspirator hose is located at the right side/rear of the control panel.
NOTE:
If the hose was disconnected, re-connect the hose and repeat the paper test procedure.
2. Remove the radio to get access to the hose and the clamp on the evaporator box.
3. Refer to the picture for properly routing the hose.
NOTE:
One end of the hose is connected to the aspirator on the heater housing near the accelerator pedal (hose = 26.5").
Normal operation of the in-car temperature sensor:
The in-car temperature sensor is located approximately 1" (25 mm) behind the grill of the control panel. An aspirator (device that creates vacuum) is mounted on the heater housing near the throttle pedal. As air blows through the aspirator, a vacuum is created. The aspirator hose is connected on one end to the aspirator, and the other end to the back side of the control panel, just behind the in-car temperature sensor. When the blower motor is switched "on", cabin air is drawn through the grill and past the in-car temperature sensor.
A kink in the aspirator hose or a disconnected hose prevents air flow over the in-car temperature sensor. Heat generation (especially by the radio or CD player) in the center console "warms" the in-car sensor, sending a false signal to the control panel. When the heat in the center console is higher than the passenger cabin temperature, the FATC control panel interprets the signal as "the vehicle is above temperature", and switches (moves) the temperature blend door to cool the vehicle. The warmer the center console becomes, the colder the vent temperatures become. The condition is even more apparent if the air conditioner is switched "on".
WARRANTY INFORMATION: