Nissan Repair: A/C not working when temp above normal, thermo fan, airconditioning system

Question
I have a 1998 nissan patrol ti 4.5l petrol. the a/c ( climate control )cuts out when the engine temp rises slightly. Is this normal? Is there a a/c cut out switch or sensor I can check? I do a lot of heavy towing so the car temp is usually always higher that normal especially when the ambient temp is above 30dec celsius. I have had a new radiator and thermo fan installed and the a/c regased. I would be happy to disable the cut out if that is possible.

Answer
Neville,

It sounds as if the pressure in the airconditioning system is too high when it becomes inoperative.  That is, when the temperature rises there is a a pressure switch that cuts out the airconditioner.  You could augment the system with an electric fan that would provide additional cooling or have the system pressure checked, on the airconditioner, when it cuts out and verify that it is overtemperature that is causing the compressor to cut out.  From my experience this is the cause of the problem.  You could have the refrigerant pressure lessened by removal of a small portion and see if that resolves the issue.  But, augmenting with an additional cooling fan usually works and it quite inexpensive.  You cannot really disable the compressor cutout as it is a safety feature.  And, it is the switch that cycles the compressor under normal use.