Insufficient information, please ask the question
in a sensible clear way.
If you are talking about checking to see if the charge is right, yes it must be running.
No, you use the ohms position.
No, the circuit should not be energized when checking the resistance of a circuit.
Try checking the low pressure switch.
If your AC unit is not turning on, you can try checking the thermostat settings, ensuring the power supply is connected, checking the circuit breaker, and cleaning or replacing the air filter. If these steps do not resolve the issue, it may be best to contact a professional HVAC technician for further assistance.
You can tell if your AC is frozen by checking for ice buildup on the coils or pipes, reduced airflow, warm air coming from the vents, and unusual noises. If you suspect your AC is frozen, turn it off to allow it to thaw and contact a professional for assistance.
The way that you know if your ac in your vehicle needs to be charged is by checking the psi level on the ac system. You check the level with a gauge throught the low side port on your ac system. There is a great web site www.idqusa.com that has alot of helpfull information about your ac system.
Start out by checking the a/c blower and the blower resister.......
try checking main fuse box located in top of dashboard release clip located just above where the ac switch is (or would be if the vehicle doesnt have ac fitted)
First thing check to see if you have any freon in the system and if so start checking the electrical for the blowers.....
Start out by checking the freon levels and if that is okay then check the pressure switches and the wire harness to the clutch....
I would start by checking the fuse, the relay, and the connector on the blower itself.