Mazda TC070-15-01H, Student Manual

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AIR CONDITIONING
SG02 - Control System [Manual Air Conditioning]
SG02-8
TC070-15-01H
Look at both graphs, “Temperature – Resistance” and “Temperature – Voltage (PCM
input)” and read the resistance and voltage at each given temperature as below.
Resistance kilo-ohm, Voltage V at -10 ºC
Resistance kilo-ohm, Voltage V at 0 ºC
Resistance kilo-ohm, Voltage V at 10 ºC
Insert “higher” or “lower” in the blanks of the explanation below.
The higher temperature it senses, the resistance it creates, therefore the
CPU detects voltage.
Look at the wiring diagram below. The left one shows the circuit of evaporator
temperature sensor extracted from the control system wiring diagram. And the right
one is a rearranged diagram of the circuit.
The evaporator temperature sensor is grounded through the climate control unit. The
circuit operates with 5 V power supply. The voltage between the resister R and the
evaporator temperature sensor varies according to the temperature that the sensor
senses. The CPU detects this variation of the voltage (potential) which is equivalent
at the terminal N of the climate control unit.
What do you think is the voltage at the terminal N if the resistance of the evaporator
temperature sensor is 0 ohm?
V
What do you think is the voltage at the terminal N if the resistance of the evaporator
temperature sensor is infinity?
V
Apply the ohm’s low and calculate the constant value of the resister R’s resistance.
ohm