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INSIDE TEMPERATURE SENSOR
Inside Temperature Sensor (ITS) is located on right side of steering column, next to ignition
switch, in a dedicated vent. Sensor resistance changes as temperature of air inside vehicle
changes. Sensor low current signal corresponds to actual in-car temperature. Signal is monitored
by HVAC control head, which controls blower speed and temperature door position to obtain
desired temperature.
SUNLOAD TEMPERATURE SENSOR
Sunload Temperature Sensor (STS) is located on instrument panel center defroster grille. Sensor
is a photosensitive resistor, which measures amount of heat generated by sun shining into vehicle.
VACUUM/ELECTRIC SOLENOID
Vacuum/electric solenoid is located on left side of HVAC module above blower motor. The
module converts electrical signals from A/C-heater control head into vacuum signals. Vacuum is
constantly applied to module and when commanded, vacuum is routed to various mode door
control actuators.
TROUBLE SHOOTING
DIAGNOSTIC SYSTEM CHECK
1. Connect scan tool to Data Link Connector (DLC). Turn ignition on and check that scan tool
powers up. If scan tool does not power up, check DLC circuits (battery voltage at terminal
No. 16, ground at terminal No. 4 and common signal ground at terminal No. 5). See DATA
LINK CONNECTORS article in WIRING DIAGRAMS. If scan tool powers up, go to next
step.
2. Turn ignition on (engine off). Attempt to establish communication with HVAC control
head, body control module and powertrain control module. If scan tool cannot communicate
with module(s), see SCAN TOOL DOES NOT COMMUNICATE WITH CLASS 2
DEVICE in appropriate BODY CONTROL MODULES article in ACCESSORIES &
EQUIPMENT. If scan tool communicates with module(s), go to next step.
3. Select the DTC display function for HVAC control module, body control module and
powertrain control module. If any DTCs are displayed, go to next step. If no DTCs are
displayed, diagnose HVAC system by symptom. See SYMPTOM TESTS .
4. If scan tool displays any DTCs that begin with "U", see SCAN TOOL DOES NOT
COMMUNICATE WITH CLASS 2 DEVICE in appropriate BODY CONTROL
MODULES article in ACCESSORIES & EQUIPMENT. The presence of a DTC which
2001 Chevrolet Corvette
2000-01 AUTOMATIC A/C-HEATER SYSTEMS Corvette
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