Nissan Repair: 1994 nissan maxima a\c, volt ohm meter, nissan maxima

Question
HI I am having a a|c problem with my 94 nissan maxima. the air runs fine on low #1 medium #2 and #3 but when we put the air on #4 high it will work for awile then for no reason the compressor will kick off and the cool air becomes warm. So we turn it off then back to #3 and its back on. this will happen in idle or going down the freeway at 65 mph for some reason the compressor always kicks off on high. the freon is fine and we reciently had expanson valves replaced HELP we live in Arizona and we need a good running a\c  

Answer
Dirk,

I would remove the resistor set and check it with a volt/ohm meter.  On high the system should have no resistance.  But, it sounds like the switch is going out and not the resistor.  So, wiggle the switch while on high and see if it is intermittent.