Anyone running AC with an aftermarket/NO Ecu?
If so, how are you triggering the ECU?
How hard would it be to try and run AC without an ECU, what is involved?

Ok maybe I am wrong here, but here is what I thought. Is that the AC compressor is engaged through the switch, the relay....and that activates a solenoid that engages the compressor. I didnt think the ECU had anyhting to do with it. Can someone approve or disprove this??

The ECU does control the A/C engagement. NO idea how to get around it with an aftermarket ECU other than leaving the factory ECU there taking inputs from all the sensors and left the aftermarket control the timing and fuel.

Terry

how often does it cycle? Presumable you could program a PIC to control the relay and just cycle it. Does the ECU make the A/C cut when you increase throttle? That'd be a nice thing to program into it if you went this way.

nope AC stays full on. Cycle time varies according to the temp I think, Well It sounds like it does.

The largest thing IMO would be the extra load and the aux fan.

That shouldn't be too difficult to program, tap into the temp sensor and TPS (I'm still going to push for killing the A/C when you hit the trottle) and let it run full out under normal circumstances.

What "aftermarket" ECU are we talking about? As far as I knew, there was only one - from AFX - and it controls AC just fine. :wary

I guess you could, with a pic or BS.

Originally posted by DR1665
What "aftermarket" ECU are we talking about? As far as I knew, there was only one - from AFX - and it controls AC just fine. :wary

Perhaps he's using either MSnS as full standalone, or the other one I forget the name of.

**EDIT**
There's a low pressure switch that typically triggers when to kick on the A/C. If you were to run a relay that only armed when the A/C was on and when the low pressure switch opened (or closed), you could kick the A/C compressor on or off.

The next step would be to set up a hard acceleration switch (or output from the ECU) that turned the A/C off above like 75% throttle or something.

All you have to do is engage the clutch. One wire, 12v+. Easy enough.

Fuck low pressure switches, PICs, and the orange light on/off cycle.

but would it be wise for the compressor to be constatly on if it doesnt have to be? I dont think so, atleast I wouldnt want it to.

It is *anyway*. The ECU will turn it off if the pressure switch goes too low. other than that, if the button is on, the compressor is engaged. It doesn't have a duty cycle.

The only downfall I see to have it run all the time is the evaporator will freeze up, at least it did when I turned my low pressure switch down too far. Of course, all you have to do is turn the fan on high for a few seconds and it thaws.

you sure its on ALL the time? I can distinctly hear it clicking on and off.

Originally posted by Chamuko
you sure its on ALL the time? I can distinctly hear it clicking on and off.

it depends. the GS has two modes - a low and a high. orange light is low, and it clicks on and off. Green is high, it's always on. You may hear the condensor fan click on and off, but the compressor, AFAIK, is always engaged when the light is green.

Easy enough to verify - turn the AC on and watch the compressor. You should be able to see it engage and disengage the clutch, if it does.

Originally posted by DarkOne

Originally posted by Chamuko you sure its on ALL the time? I can distinctly hear it clicking on and off.

it depends. the GS has two modes - a low and a high. orange light is low, and it clicks on and off. Green is high, it's always on. You may hear the condensor fan click on and off, but the compressor, AFAIK, is always engaged when the light is green. Easy enough to verify - turn the AC on and watch the compressor. You should be able to see it engage and disengage the clutch, if it does.

I have. And I know what the fans sound like compared to the compressor, c'mon Dino ( helps that they arnt the oem).

Compressor sounds like the AT use to sound, like a ratchety sound.

Originally posted by DarkOne

Originally posted by Chamuko you sure its on ALL the time? I can distinctly hear it clicking on and off.

it depends. the GS has two modes - a low and a high.

That has got to be on 95s only or maybe early 96s. Mine (98) only has green. On and off.

yup, wasnt that discussed here long ago? 98 here also.

My 95 RS has the dual position setting. I didn't remember my 99 GS having it, so I was somewhat pleased. I assumed it's like MAX A/C vs NORM A/C in other vehicles.

Originally posted by DarkOne
All you have to do is engage the clutch. One wire, 12v+. Easy enough. Fuck low pressure switches, PICs, and the orange light on/off cycle.

More details please, what do you mean engage the clutch?

Originally posted by Chamuko
you sure its on ALL the time? I can distinctly hear it clicking on and off.

It cycles, but if you have it on max a/c with the fan on high, chances are it will be on 100% of the time. And don't forget, we're in TX, it's been 99+ for several straight weeks with no rain here in SA.

Originally posted by rhui

Originally posted by DarkOne All you have to do is engage the clutch. One wire, 12v+. Easy enough. Fuck low pressure switches, PICs, and the orange light on/off cycle.

More details please, what do you mean engage the clutch?

The A/C clutch? You know, that allows the belt to turn withouth turning the A/C compressor?