| After much research I finally concluded the reason my a/c cooled poorly was a malfunctioning TCA. This is an evaporator temperature thermistor, placed on the discharge face of the evaporator and very hard to reach for replacement. Not to mention the part is discontinued. Nissan still uses TCAs and current TCAs are available, and assuming they work in the same way. one of these could be used. The TCA grounds a pin in on the ECU. If the ground is not present, the ECU cuts power to the relay that powers the compressor. The TCA is supposed to do it at 34F but the broken one in my car does so at 44F, resulting in poor cooling. I finally exposed the ECU and permanently grounded the pin, therefore eliminating the TCA evap temp control function. I knew Nissan put this system in to prevent evap freeze-up under certain conditions when the oil-filled bulb controlled expansion/by pass valve would fail to do the job. Likely during auto a/c operation in humid and cool conditions. I have been using the car with the air on, in ambient temps up to 88F, without any adverse effects. With no cabin filter and 20some years of exposure, until the evap is removed and cleaned, the best performance out of the a/c will not be had. Which brings me to a question: I noticed the "econ" setting was on today and I noticed cool air coming from the vents. I remember reading on this forum (or another maybe) that econ was just Nissan's way of saying "vent". Guess not!
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