Working on my 1993 RTTT, but will be doing the same thing on my 1993 3000GT.

Replaced the AC compressor with a 1994. Replaced lines with 2ng gen ones to line up on compressor, Converted fitting to R134. Replaced AC Dryer, Replaced Condenser, Replaced Expansion valve. I also flushed out all the lines. I also added correct amount of PAG oil to compressor, dryer, and condenser.



Began to charge system, and ac clutch was not engaging. System stopped taking on more refrigerant after about 6oz "about have a 12oz can". I searched and read that some have had to bypass the clutch relay to get the system to pull in more refrigerant. I did that and the system pulled in 24 oz. However when I replaced the clutch relay the system will still not engage the clutch.



I checked the pressure switch on the top of the dryer. When I unplug it the RPMs on the car drop.

Also my ac fans are working correctly.

With the clutch relay bypassed the system seems to operate normally blowing out nice and cold.

Trying to see if anyone else has done this swap, and if there is a known issue or work around. I have been scouring here, 3si, and the internet with no luck.