AC Clutch: The parameter indicates On whenever the powertrain
control module (PCM) energizes the A/C compressor clutch relay. Engaging the A/C
compressor clutch relay will also engage the cooling fan at low speed.
AC Request Signal: This parameter indicates whether the A/C
switch on the instrument panel (IP) has been selected.
ECT Sensor: The scan tool range is -40 to +140°C (-40
to +284°F). The engine coolant temperature (ECT) sensor is a thermistor which
changes internal resistance as the temperature changes. When the
sensor is cold, internal resistance high, the powertrain control
module (PCM) monitors a high signal voltage and interprets the voltage
as a cold engine. As the sensor warms, internal resistance decreases,
the voltage signal decreases and the PCM interprets the lower
voltage as a warm engine.