I have a 1991 Nissan 300ZX with the following problem. The A/C /Heater will not stay on.

I haven't had this problem. If I do experience this condition, I would take it to a repair shop and have them vacuum the air out, check for leaks and refill with new Freon. It sounds like you might have low fluid in the system.

the pod, assume sight glass on water filter. low Freon causes bubbles going around

How is low fluid going to cause a flutter of the electrical connections on the a/c heater small screen which shows what temp you have set the a/c for inside the car?

its not, thought you were looking at another area, the screen no doubt has a control unit somewhere that does it all! including compressor activation .a ZX forum would be the place to pinpoint location of device! Z cars are complex with electronic circuts

Hello IRVDANIEL, I also have a 1991 30ZX and I am experiencing the same intermittent problem. Originally thought it was a low battery (12.03 volts) because radio was also acting up, but not the case now with new battery. The symptom is that the electrical power goes "out" to the AC display control panel, making the screen go blank, but also all of the ac controls. Did you ever figure out the problem? chris4sail

I have a 91 300tt. It also has a compressor that is pulsing on and off. The system has been flushed and recharged, I checked the ac air amplifier and all the sensors. It still pulses. I have an aem stand alone fuel management system and we have checked that also.

I have a Nissan 300zx 1991 and my problem is that my ac won’t go lower then 60 degrees and the front ac vents won’t blow air only the vents on top for the window.can someone tell what’s wrong?