Isuzu 2000 Trooper Workshop Manual page 124

Duct Sensor
The duct sensor is the sensor to detect temperature
change of the side of evaporator blower coming by fresh
recirculation of intake door or "on" "off" of compressor.
The temperature is converted to resistant rate.
And it works as thermostat to control to prevent freezing
of evaporator.
This sensor is installed in the upper case of evaporator.
Legend
(1) Duct Sensor
(2) Electro Thermo
(3) Evaporator
HEATING, VENTILATION AND AIR CONDITIONING (HVAC) 1A–95
Sun Sensor
It is a photodiode used for detecting quantity of solar
radiation.
generated by changes in the interior temperature (which
results from fluctuations in solar radiation) into
photoelectric current to enter into the automatic heater/air
conditioner control unit.
This sensor is provided at top of the defroster grill.
860RY00007
Legend
(1) Sun Sensor
Power Transistor
Receiving base current from the automatic heater/air
conditioner control unit, the power transistor implements
stage–less speed change of the blower fan motor. This
transistor is provided on the evaporator.
Legend
(1) Evaporator Assembly
(2) Power Transistor
This sensor converts the offset signal
826RY00012
874RY00011