AC mag clutch and ECU wiring question

[Mat Grant]

Hi,

I'm fitting a 1uz from a soarer into a lotus, I'm wiring in an AC relay, I have a couple of questions:

I'm presuming the AC clutch is fed with 12v and it grounds through the block to activate the AC compressor - is this correct?

On the 1992 sc400 wiring diagram there is a white wire that says "A/C magnetic clutch relay" - is this the ECU driving the AC on and off, or is it feedback to the ECU to tell the ECU when the AC is on or off? I want to run the AC directly off a switch button in my heater panel, but if I need to provide a signal or a closure to ground to tell the ECU when the ac is on I will wire it.

Finally - I don't have the relay block out of the soarer - does anyone know what colour the wire to the mag clutch is, and what route it takes through the engine, what the plug looks like etc?

Any info gratefully received.

Cheers, Mat.

 

[George_R]

ECU reseives AC control signal and engages the clutch. It however temporarily disengages it when maximum power output is needed

 

[samsdad]

The ECU also increases the idle speed when the compressor is running

 

[Mat Grant]

Hi,

Thanks for the replies - so in that case the white wire that is labelled "to AC relay" must be from the ECU to the relay that turns the AC on and off.

If so I'd like to wire that, rather than have the AC direct off the button on the heater panel (not a soarer one - but a direct button for AC on/off) driving the ac mag clutch, I'd like to have it wired through the ECU.

So that means I have to identify the way the ECU receives the signal from the driver when they want to turn the AC on.

Does anyone know how this happens? Is it just a case of finding the right pin on the ECU that is open/close or 12v/0v

Any info appreciated. Worst case I can just wire the AC direct, but it would be good to do it properly.

Thanks, Mat.

 

[Bushwhacker]

I'll scan the A/C wiring diagram for you later Mat and add it to this thread. Screen captures won't show the whole diagram for some reason.

Magnetic clutch wire is blue by the way. (According to the diagram)

 

[Mat Grant]

Hi Vince, thanks that would be great.

btw did you get my message about the loom?

Cheers, Mat.