trinary switch..........hmmmmmmmm.
how about racecarl is on to something, and probably closer to right. my guess, (like everyone else's) is undercharge or over charge, and probably undercharge. at road speed, the air movement blows off more heat from the condenser, and causes a low pressure condition on the low side, where the clutch cycling switch is located, and causes the switch to shut down the compressor. another possibility is the increased pressure at higher rpm's causes an increase in the high side, and the high limit kicks it off. in either case, the only way to tell is with a set of gauges being read at road speed. i have a set of gauges i use for thermoking work, and the hoses are 9 feet long.
sort of duct taping yourself to the fender and hitting the interstate, how about putting a good sized blower fan positioned to where the condenser is, and running the r.p.m's to highway speed. nah......... do the duct tape thing.........and take pictures.......
