JZX90 1JZ in MX83 air con idle up

[Hengsta]

What he said ^^^

[Hipsi]

I had a go at hooking mine up today since I've just had it gassed. Was a lime green wire for me too so I hooked it up to pin 8 on the B3 plug and also to the ACMG pin on the ECU but when I turn the AC on it doesn't actuate the mag clutch. I have tested it by putting 12V straight to the wire on the compressor and this works. I just can't seem to get a 12V signal that is switched by the AC button. It's driving me crazy!

For anyone else interested here is the wiring diagram I used to hook the a/c up. I have added the relay bit for the idle up.

There is one other wire to hook up that isn't shown on this diagram, it gives power to the a/c clutch and will be located on one of the 3 grey JZX90 loom plugs that should be sitting in behind your glovebox (depending on how your conversion wiring has been done).

I found it by doing a continuity test between the wire on top of the a/c compressor and the JZX90 loom plugs. I think from memory it was on the smallest of the 3 plugs, and was lime green on my loom.

Anyway, when you find that wire, it also needs to be connected to pin 8 on figure 3 of the attached diagram, so that the a/c clutch gets +12v when the air con is turned on.

[dumbass]

that diag is not exactly correct
says to hook up acmg wire to pin 8 a/c wire on fig 3
the mx83 doesnt have an scmg wire so u dont need it
acmg wire triggers the ac relay on zx90 ac system
cressida ac relay is turned on by the ac amplifier or ac ecu if u dont know what amplifier is
and the only wire on mx83 that goes to ecu is to a/c pin which just tells ecu to idle it up
if u have hooked up black/white wire from under dash for ac compressor to the compressor
and it still doesnt turn on u have issues with presure sensors or something with ac amplifier
nothing to do with the ecu

[Hipsi]

Your awesome mate, thanks for that I'll give it a shot tomorrow. At least as you say if that doesn't work then I can look into the ac amp. Where is that located by the way (just in case).

[dumbass]

in that pdf
fig 3 pin 8 is black/white
that wire should go to the a/c compressor clutch wire
disregard the acmg wire in the ecu
the mx83 i think uses engine rpm as reference to turn off ac comp at hi revs
and im not sure but some cars need rpm to ac amplifier for ac to cut it but not sure if mx83 is same
so does ry tacho work

[Hipsi]

yeh tacho works after I made up the booster that was on here somewhere. Tried disconnecting the acmg wire and still nothing. I'm not getting 12v on the black and white wire

[Hipsi]

Don't know if this helps but the AC fuse gets 12v when the fan I turned on regardless of whether the AC button is pressed

[Hipsi]

I've checked that pin in the junction block. It's actually earthed for some reason because I get continuity between it and any earth. It's no wonder I'm not getting any Voltage on it. Now what!

[dumbass]

u cant use continuity on somehtign liek that
that black white wire connects to ac clutch so u will measure earth regardless
just use voltge for that
sounds like yr ac amplifier is not giving 12v out due to it not recieving a signal form a sensor or something similar
hard to say without knowing whats been done previously
but sounds like its not the fault of the conversion
u either have no gas or sensor not working

[Hipsi]

Definitely have gas. Any suggestion on what sensor I need to be checking?

[dumbass]

most fo the time the ac works if u hook up the blac white wire
was it working before conversion
do u have the ac diags for mx83
who wired up the car
maybe get them to go over it
did they just splice it in under the dash or did they run the whole jzx dash wiring aswell
could be issues there hard to say where issue is
u might need to start testing the ac amplifier

[Hipsi]

I've now come to realise that my ECU may not be wired up entirely correctly since my cressida ECU harness colours don't exactly match the coloured '89 mx83 wiring diagram that's floating around. I never had a 22 pin plug on there, it was cut off when I got the car so I guess I just made some of it up for lack of the correct colours. Dammit.

[Hipsi]

So I grabbed a 7M 22-pin plug and harness clip from the wreckers today and made sure all my 1J wiring into the Cressy loom is dandy which it is. The only ones I haven't connected is the overdrive switch and the A/T indicator switches. While I'm loathed to do it I'm considering hooking up a toggle switch for the aircon. The only other thing I can think to do is swap the aircon amp.

[JP]

the AC should still work in the MX83 without any input from the Engine ECU. The 7M's "AC" ECU pin is just an input. I'd be double-checking all the related fuses/relays etc.

I put the AC wiring together in a single file for you here: http://www.purcellperformance.com/Tech/MX83_AC_EWD.pdf

[Hipsi]

Love your work. I was a bit doubtful that the ECU wiring could affect the aircon, but I've been clutching as straws. I'll work my way thru the diagram and hopefully come up with a solution.