Fun With New Old Cars!

[85 Cutlass Brougham]

Well, I have a curious new problem with my Nissan. It's the A/C compressor clutch. It turns on whenever the ignition is off, and turns off when the ignition switch is turned on... WTF? The clutch is switched on and off by the computer, which makes me think it has gone berserk. No other systems are affected either, just the A/C. I have the FSM and the schematics for the A/C system too, but they are of little help other than to tell me that my suspicions may be right. Any thoughts?


BTW, for those who don't know what it is, it's a 1998 Nissan Frontier 4 cyl/ 5 speed. It has fairly low miles too as it has only just turned 320,000.

 

[dan2286]

What sensors/parameters tells the computer the a/c needs to be on? Whatever they are, check for voltage at the corresponding pins at the PCM connection. I would think there should be none. If nothing is telling the computer to turn the compressor on, then the computer is probably done.