ronarndt

Does anyone know where the fuse is for the air conditioner compressor clutch on a 1990 GTUs? My compressor died and froze up the clutch as it went. I have the new compressor installed, but now the A/C switch on the dash does not activate the compressor clutch. The switch lights up when pressed, but it does not activate the A/C. I had to direct wire the A/C compressor clutch wire to the battery to re-charge the refrigerant. I have checked every fuse in the fuse block and they are good. My wiring diagram does not show where the fuse would be, but every car I have ever had has a fuse (usually a separate one) for the air conditioner. Any help will be appreciated, so I do not have to spend an entire day tracing the wire by hand.
Ron A.

Icemark

There is not a fuse for the Compressor clutch. The compressor clutch gets its signal from the air condition relay which is controlled by the ECU (the ECU only allows the relay to work if there is sufficent refrigerant in the system).

I'd say you didn't vacume and fill the system correctly when you replaced the compressor and there is still not enough refrigerant in the system.

HAILERS

Try looking at this https://www.rx7club.com/forum/showth...hreadid=191923 look for HaILERS and in the response I attached a url. Click the url. There should be a schematic of the series four a/c system. You need to check the voltage at the a/c relay in front of the radiator and also the pressure switch leads on the drier. You might jumper them (the drier plugs) to verify that there is/is not enough pressure in the system. Gotta work now. Later.

J-Rat

iTrader: (2)

Most systems have a high/low/high switch on the reciever/drier. If there isnt enough refrigerant, your compressor wont engeage.

Jarrett

ronarndt

Hailers- I copied your schematic for the A/C circuit. Thanks. I have the FSM for my 3rd gen but only a Hayes repair manual for my 2nd gen. It is not much help for the A/C stuff. Any idea what the high side pressure is supposed to be? I have enough refrigerant based on lack of bubbles in the sight glass on the receiver drier, but an actual number to work with would be helpful. The A/C puts out tons of cold air when I hot wire the compressor clutch, but I don't want to have to do that. I'll check the voltage at the pressure switch tomorrow- thought it was only a high pressure cut-off switch, but using it to activate under minimum required pressure makes sense also- those crafty Mazda engineers with their kansei engineering.
Ron A.

SureShot

Back to the origonal question - The AC clutch power is from the "Cigar" fuse.

It's partly because all US AC is dealer/port installed.

HAILERS

Try lighting a cigar then. If you can.......

The 91 manual says.....NORMAL PRESSURE AT 77 DEGREES F...AS FOLLOWS:

Low Pressure: 14-24psi
High Pressure: 149-192psi

That's for R-12, not R-134

I'm not a a/c person. I did have a/c problems. The previous owner/abuser had jumpered a switch to the compressor to make it work. I went to the relay in front of the radiator and found problems. I had 12v and a ground with the a/c turned to on. So I did replace the relay and the thing worked.

Just jumper the two prong connector at the drier and see what happens. If it runs, then the pressure is low (doubtful since you have been getting cold air), or the switch is bad.

I think I'll pull my Cigar fuse sometime to check it out. SureShot probably is right and the diagram is not because of the dealer install situation. Makes sense.

ronarndt

Checked the cigar lighter fuse- again- found it was bad. Not sure whether I missed it when I checked last time, but now everything works without having to hot wire anything. Plus- I now have a decent wiring diagram for the system- Thanks.
Ron A

HAILERS

I need to pay more attention to what SureShot says in the future.

Terry Norris

I converted my sons 89 GTU to the R-134 and when I started the car to put the R-134 in the system the compressor would not come on. I had the AC button in at the time. I connected the freon and after a very short time the compressor kicked on and the AC has been cold now for over 2 weeks and counting. Like the above reply, the compressor will not work without the correct amount of freon in the system.

gbowers

Terry, please indicate how to convert air conditioner to R-134 - please show steps.

Thanks,

Gordon