This happens when the clutch is commanded to be engaged, but the compressor rpm measures slower than expected (including zero) versus the engine rpm. The A/C amplifier assumes the belt and/or clutch is slipping and is about to burn up. So it will lock out the A/C.
As you have read, there are a lot of parts involved. First step is to see if the clutch does engage and spin normally (for a second) before the light starts blinking. That would indicate a problem with the measurement. If the clutch doesn't even try to engage, or it engages and slips, something more fundamental is wrong.
Low charge will not cause it. Low charge makes the compressor easier to turn than normal.
Last edited by mk378; 06/03/20 05:31 PM.