Toyota Service : Hello. Welcome to Just Answer. Please allow me to assist you.
Toyota Service : Hi.
Toyota Service : Is the vehicle available?
No, it is at our sons place at present.
Toyota Service : Ok
Toyota Service : There are two main causes for the AC light to flash, neither of them include freon charge
LAst night I insatlled a set of AC gauges and that is when i found the pressure in the system. I alos tested the Refrigerant and found it was 100% R134A
Toyota Service : The most common cause is a failed compressor RPM sensor, the other is a bad compressor clutch relay
Where do i find the compressor clutch relay?
Toyota Service : It is labeled "MG CL" or " MG CLUTCH" in the relay box under the hood
How can i test the RPM sensor?
Is there any way to test the relay by jumping out the terminals?
Toyota Service : The RPM sensor is located on the side of the compressor.
How can I test the RPM sensor?
Toyota Service : You can take the relay apart, and manually trigger the contacts, if they are not clicking together when the AC button is depressed
You can hear the clutch come on momentarily and then it realses and the flashing light comes on
Toyota Service : If the light continues to flash, the RPM sensor is not transmitting the compressor speed to the AC amplifier
Toyota Service : I am inclined to believe the RPM sensor is bad
I will see how i can change the sensor and see if that makes any difference.