Help rewiring AC to Haltech

[Draimond]

The Haltech needs an input so it knows to turn on the AC DPO.
Which is what I need the 5V for. All the AVI's on the Haltech are 5V as far as I'm aware.

 

[Draimond]

Bit easier to see what's going on in this photo.

 

[Draimond]

I still have no clue where the thermostat switch is....

Not sure about that high temp cutout they're showing just before the compressor either. There's literally nothing in between the compressor and the AC relay on that wire.

I'm currently stuck trying to find the link or wire that connects the interior controls to the engine bay side.

I've got my brown wire located from the AC switch but I'm not sure where that goes. Allegedly it goes to a thermostat switch but again I've got no idea. It doesn't connect to the coolant temp sensor.

And the brown wire coming out of the AC pressure switch gets spliced into the brown wire in the AC relay. But there's no continuity between the brown wire in the AC relay and the brown wire on the interior AC button.
And besides that brown wire coming out of the AC relay goes to E11 on the factory PCM.

 

[Draimond]

Hold up...... I haven't had working AC in my VS in.... Half a decade at least... So I'm a little rusty...

Can you turn an AC and heater on at the same time? I can't see anything without pulling more of my dash apart but I'm betting that the thermostat switch is part of the interior climate control stuff, but there's no accessible wires cause it's all vacuum controlled... So I'm assuming there's a switch in there that turns the AC off then you pull the heater open....

The brown AC button wire disappears down the back of the dash and the green and black wire from the AC pressure switch definitely goes through the firewall with the BCM loom. That thermostat switch has to be buried up the guts.

 

[Draimond]

Wire 1 will get full 12vdc.
It likely has a current/voltage shunt in the OE module.
So you would only want to use the DPO as that should be 12vdc.

Yeah yeah, so it should only get that 12V if the interior AC button is switched on and the pressure switch is happy. So I can use that 12V to turn on a relay to pass 5V from and back into Haltech acting as the on switch.

 

[ephect]

Thermostat switch I believe is in the evaporator, with detects if it's cold or not to control the ac.

Yes you can have the ac with heat, which allows you to get other temperatures other than freezing or boiling.

 

[shane_3800]

The A/C switch I would take a signal off that at 12vdc, then you need to buy one of those solid state modules to drop it down to 5vdc for the ECU, maybe haltech has them? then connect the DPO to the clutch relay.
I think that should work, I might be wrong, waiting on Lout or one of the other auto electricians.

I'm a mechanic not and auto elec.

 

[BlackVXGTS]

Why are you doing this? Normally the Haltec is used for engine control and the normal Holden ECM/PCM is used to perform all the other remaining functions (such as A/C). That's certainly how Motec does it, and I'd be surprised if Haltec wasn't the same (although I could be wrong).

 

[shane_3800]

Why are you doing this? Normally the Haltec is used for engine control and the normal Holden ECM/PCM is used to perform all the other remaining functions (such as A/C). That's certainly how Motec does it, and I'd be surprised if Haltec wasn't the same (although I could be wrong).

I believe he is doing this so he can have the engine idle up when the A/C kicks in.

 

[Draimond]

Why are you doing this? Normally the Haltec is used for engine control and the normal Holden ECM/PCM is used to perform all the other remaining functions (such as A/C). That's certainly how Motec does it, and I'd be surprised if Haltec wasn't the same (although I could be wrong).

I'm using the Haltech Elite 2000 as a stand alone ECU.

NO piggy back.
DFI delete, sequential ignition with LS1 coils.
Wideband, flex fuel, boost control.
Plus all possible factory functions including carbon canister purge.

(Yes I've maxed out the inputs and outputs on the elite 2000)

Retaining the factory BCM.

Why? I want AC haha..
Well the AC is just 2 wires and a relay.
It's probably more work with a worse result to keep the Holden PCM.
This is the easy part, I still need to make custom AC gas lines and connectors to accommodate for the turbo taking up space.

Haltech has put a lot of work into being a general solution to do everything.

As Shane said, you get idle offset and rpm cut off. More if you hook up temp and pressure sensors.

Plenty of work ahead of me, but I'll come back to this thread with pictures of the install and some follow up on results when it's back on the road... One day.