On 2007 Fit the a/c operation is controlled by main ECU



The ECU will energize a/c clutch and turn fans ON if:
The line pressure switch is closed;
The compressor housing is not overheated
The engine is not overheated
The a/c evaporator temperature is above certain level
The main switch is pushed in (or mode switch is on defroster position)
The blower motor is turned on

By pushing on the a/c switch (or selecting defrost) on the instrument panel we are connecting the blue/white wire from ECU a/c signal circuit to the ground (connector E, cavity 28).
The current flow trough a/c signal circuit is described below:
ECU, overtemp swich, pressure switch, a/c switch (or mode switch) on the dashboard, blower motor switch, ground (red line, ECU connector not shown)



So when any of these switches are open the a/c will be off.
In order to check the thermocouple, use digital high impedance voltmeter (No test light, Por Favor!)
Hook up the positive probe like this:



Connect negative probe to a good ground using alligator clips
Start the engine and turn a/c on the voltage will vary according to the temperature of the air going past the probe
On my car the compressor clutch kicks in when voltage is below 3.5 V and turns off at 3.6 volts
(75 degrees F ambient, blower at 2nd speed)
I took the “video in action”; not sure if my a/c cycles too often