Aristo (JZS147) vs Supra (JZA80) Air Con Wiring to ECU

[wilbo666]

Well I recall that when mr1j put a JZA80 ECU in his Aristo his AC didn't work...

The wiring diagrams that I have (GS300 and JZA80) all seem to show the same pins?

Is what I have listed below correct?

ECU Plug A (40pin Plug) : Pin 34
AC Signal [INPUT] -> (12V = AC on)

ECU Plug A (40pin Plug) : Pin 23
AC MG [OUTPUT] -> Active GND (Via NPN) to trigger AC MG Relay ON (And hence turn AC ON)

I'd like to wire my AC up as per the proper Aristo setup But as I don't have a half cut, I can't trace the wires, and seeing as most of the diagrams seem to be JZA80 I'm not sure if what I have is right!

Otherwise I'm going to hit Esteban up and go trace it off an Aristo...

Cheers
Wilbo

[madmont]

According to the Aristo wiring diagram I posted pin 34 is the input to make it work. Pin 23 is the output which gives earth to the a/c relay to make the a/c clutch work

[wilbo666]

According to the Aristo wiring diagram I posted pin 34 is the input to make it work. Pin 23 is the output which gives earth to the a/c relay to make the a/c clutch work

Cool that is what I have already! Do you have yours wired up in that fashion and working?

Cheers
Wilbo

[madmont]

My air conditioning works . If I remember right I connected it up to the MX83 system and bypassed the Supra ecu The MX83 a/c ecu controls the compressor directly and a wire goes back to the engine ecu to tell it is on
Here are the diagrams if you are interested
http://members.optusnet.com.au/madmont/aristo ac.jpg
http://members.optusnet.com.au/madmont/supra ac.jpg

[PlacentaJuan]

i thought the mx83 had its own a/c ecu?

aristo with jza80 ecu = no aircon. (hectic luxury spec climate control)

my car has aircon no matter what ecu i am using.

[wilbo666]

aristo with jza80 ecu = no aircon. (hectic luxury spec climate control)

This is what I've heard...any idea why?

The wiring diagrams seems to show them as being the same?!



Cheers
Wilbo

[Mos]

The difference *could* be that the JZS147 has positive signal for AC input to the ECU, and the JZA80 has negative AC input to the ECU. Most have positive input, JZZ3- VVTi has negative input, so others may too.
One would check the hypothesis by measuring the voltage on the AC input pin of the ECU and if it's normally around 12V you would then try grounding it (through a test light if you want to be safe) and seeing what happens.

Jesse, does your engine idle up with the JZA80 ECU when you turn air con on?

Mos.

[PlacentaJuan]

yea im pretty sure it does.

it certainly doesnt get rough and have issues getting close to stalling.

i will confirm this once the car is back together....

[cambelt]

The A/C is the least of the worry , as long as the ecu has the positive feed into the A/C pin it will idle up ok .If you hook it up through the ecu ( with the mag cl out pin ) i think under flat throttle the A/C cuts out .
Its the difference between the trans wiring from the supra verse aristo ecu,s thats more important , I know the car still drives and shifts gears fine with the supra but the overdrive light will flash at you .
Dave

[brett_celicacoupe]

The A/C is the least of the worry , as long as the ecu has the positive feed into the A/C pin it will idle up ok .If you hook it up through the ecu ( with the mag cl out pin ) i think under flat throttle the A/C cuts out .

ive put a test light on a 1JZGTE ecu to see how the it controls ac clutch.

its only when the rate of rpm change is high, ie. floor it that the clutch momentarily disengages. its only off for about 0.5 of a second.

it doesnt care about rpm. it will keep the clutch engaged even at 6500rpm

[PlacentaJuan]

i actually thought it was more than just the a/c not working, i got the impression from mr1jz that his entire climate control was not working, rather than just the a/c.