Re: Yes another Aircon question
should be easy enough for an a/c specialist to work out what is causing the problems.
if there is little (or no) gas in the system and it is below the 'minimum' pressure then the compressor won't engage, to protect it from damage (because if the pressure if too low then there won't be sufficient gas to carry the oil round, and the compressor will burn out rapidly). if the gas is low then my understanding is they now have to test for the leak and fix it before filling with a/c gas, rather than simply fill it up and see how long it lasts before it leaks again as may have been done on owner request in the past.
can determine if it is simply low on gas by 'manually' bypassing the trinary switch low pressure test hopefully causing the compressor to engage. This is done by shorting one pair of wires on the trinary pressure switch (with the engine off/ignition on the compressor won't turn so no damage, though it will engage itself causing the loud click). If compressor does indeed ingage then most likely just low on gas so just need to ID and fix the leak. Not sure which wires need shorting on the 166 trinary switch, could assist if you had a 164...