Aircon Issue 1JZGTE

[JZA70R_92]

Hello Guys

Finally got aircon regassed by a leccy mate. It works fine only if I connect the clutch stright to 12V. have tested pressure sensor and that is fine. problem is I push the AC button and turn on fans and nothing happens. I have bridged the 12V from the AC relay plug and if I turn the air fan off the clutch goes off. it seems like the AC button doesnt work but ive swapped it into a mates car and his aircon turns on fine, so far ive swapped the ac amplifier and checked as much wiring as I can. would anyone have any ideas? I heard something about teh ecu grounding a wire to allow clutch to work.

also swapped in a goond cond ac relay no change

this is in a JZA70 supra

[Z2TT]

You would have to find a diagram and see all the components involved in the electrical system for the A/C.
Does the JZA70 have a clutch lockup sensor? These often go bad and cause problems

[JZA70R_92]

Lockup sesnor where is that? well the magnet clutch works when I apply 12volts to it.

[CrUZida]

Have a look at the TSRM MA70 wiring diagrams.
I used these to get the aircon working in my UZA70.

You need to trace the +12V leaving the switch and heading to the clutch relay.
Somewhere along the line it will stop at a relay or sensor.

[JZA70R_92]

bugger lol. on the tsrm I seem to not be able to find the "ac switch"

[JZA70R_92]

ok ive looked on tsrm cannot find the switch arghhhhhh

[CrUZida]

This is the main page you need to use.
http://www.cygnusx1.net/Supra/Librar....aspx?S=D&P=30

Pin 7 (BR) leaving the AC amplifier, it should ground when you push the AC button (and the fan is on).
Get that working, and trace it forward from there.

Looking at that diagram there is only the one pressure switch and a relay that will stop the AC clutch from engaging.

You may have to do something with the AC Water Temp Switch (I honestly can't remember what I did on the UZA70 - I think it disables the AC if the water temp gets too hot).

But this all assumes the JZA70 is the same as the MA70.

[JZA70R_92]

cheers!! found issue after focusing more on the amplifier found out it was a old MA70 one with the wiring so swapped that out and changed the relay and ac fuse in passenger kick panel! WOOT we have aircon now the bad news halfway through my drive to work with aircon on to test it just stops no more cool air!! ive gone outside now to see if will kick as maybe water temp go to hot for it but still no dice!! will try again at 4am when I finsh arghhhhhhhhhhh

[CrUZida]

My MA70 was notoriously bad for auto-climate control, although it was the heater that was stuffing up, AC was perfect.

[JZA70R_92]

ok something wierd it will dies but if I go and bridge the clutch wire with 12volts hook everything back up it would work fine for few kms then stop again!!!!!

[Z2TT]

Stop as in A/C Compressor clutch disengates, or just stops blowing cold air and begins blowing hot air?

[JZA70R_92]

AC compress clutch disengages! this morning did the same thing start car from cold comp not work open bonnet and bridge clutch wire to 12volt bluewhite wires and plug back into relay. turn ac off and on and all is ok for around 6km s then back to square one!!

[Z2TT]

So let me get this right, even with 12v applied directly to the compressor clutch, it still disengages after a short drive?

[JZA70R_92]

no I was told by leccy mate that if I keep the clutch engaged to long I can actually freeze up stuff.

I was told it could be that car runs hot so the "ac water temp sensor" causes it to switch off thing is I cannot find this sensor and also as soon as it turns off and I go and bridge the switch via relay plug to 12 volts then plug it back into relay and press AC all is sweet for couple of klms...........

[CrUZida]

You can keep the clutch engaged, there are no electronic safety systems in Toyota's of that age to prevent them from freezing up.

The MA70 ran an AC water temp sensor, it was one of the many sensors on top of the thermostat housing. But I'm not sure if the JZA70 ever ran one.