How do I hot wire my AC compressor?

[jim-clayton]

The AC compressor is controlled by the stock ECU.
I no longer have a stock ECU.
Any ideas on how to run my AC compressor. I have located the trigger wire.
I currently have it connected to a cycle timer. I cycle the compressor 30 seconds on, 30 seconds off. I can adjust the time interval if needed.

Any ideas? Will my cycle work?

It blows nice and cold but I don't want to damage my AC system.

[TheViper]

Looks like the ECU gets inputs from the Trinary Switch and allows the Compressor to work only if the pressure is within limits.
Michael

[jim-clayton]

Originally Posted by TheViper

Looks like the ECU gets inputs from the Trinary Switch and allows the Compressor to work only if the pressure is within limits.
Michael

Thanks Michael.
I started to look at the Trinary Switch. I wasn't 100 percent sure if the Trinary
is what I needed to connect to.

[rob13572468]

Originally Posted by jim-clayton

Thanks Michael.
I started to look at the Trinary Switch. I wasn't 100 percent sure if the Trinary
is what I needed to connect to.

you are on the right track... the AC button passes ground to the ECU via the trinary switch. it looks like the ground is passed thru to the ECU if the pressure is not low or high (need to confrim that on a working elise). the ECU then activates the compressor relay by also sending a ground.

in theory it might be as simple hooking the two together through an ignition activated relay. i dont know what the ECU does with the signals though... there might be some programmed logic in the ECU that also controls when the compressor is or is not activated like based on temperature,etc.

[TimMullen]

Originally Posted by rob13572468

i dont know what the ECU does with the signals though... there might be some programmed logic in the ECU that also controls when the compressor is or is not activated like based on temperature,etc.

More likely, it's simply that the ECU turns off the AC compressor whey you give it wide open throttle - a lot of cars do this.

[Beanie]

Electronic Thermostat - Cana Kit

[TheViper]

I don't think that this device addresses the issue. What is required is to take into consideration all the relevant inputs into the ECU, that though logic, control the compressor, temperature is not one of them.
Michael

Originally Posted by Beanie

Electronic Thermostat - Cana Kit

[HKFEVER]

For sure temp. is not the only control to turn on or off the compressor. We are in HK and we need as much A/C as possible, but with no reason the A/C will switch off the compressor, and I am also wonder how to keep it on full time.

[TheViper]

The compressor can not run all the time because it will freeze up. It is cycled by the Evaporator thermostat the purpose of which is to turn off the compressor just before it freezes. Have you done any of these mods IMPROVED A/C & HEATING SYSTEM
Michael

Originally Posted by HKFEVER

For sure temp. is not the only control to turn on or off the compressor. We are in HK and we need as much A/C as possible, but with no reason the A/C will switch off the compressor, and I am also wonder how to keep it on full time.

[stinkyonion]

This Zeitronix product will solve turning off the ac at full throttle:
TCAC
Installation seems simple, posted at same website.