I’ve got my haltech all setup and running currently setting up an IAC and haltech controlled fan relay I wanted to do the same with the A/c compressor.

would anyone be able to assist me with figuring out in the A/c wiring where the request signal is? Maybe I’m missing something but this is my goal

“Wire the 22RE's A/C Request signal from the cabin switch to a spare Analog Voltage Input (AVI) or Digital Pulsed Input (SPI) on the Haltech.”

I am assuming once that is located, I should be able to find the ground side of the compressor relay pretty easily to setup a DPO

any help is appreciated

 

Can I assume a "haltech" is a replacement ECU? https://www.haltech.com/ecu-buyers-guide/ In your stock truck the AC isn't controlled by (or even connected to) the ECU. Are you just trying to replace the on/off switch? I know nothing about "haltech," but I don't see that their ECUs have an output for that.

 

haltech is a standalone ECU and it can do other functions/switches/sensors. It can control A/C clutch and in this instance it can apparently just control the A/C relay and leave the amplifier in tact I just can’t decipher the diagram to find what I need

 

The line labelled "A/C Fuse" on your diagram is downstream of the A/C fuse, which gets battery through the heater relay (this assures the compressor won't start unless the heater blower is running). L-W on your diagram, but L-R on mine. When the A/C switch is pressed, it connects that switched (by the relay) battery voltage to B-Y line to the A/C amplifier (your diagram shows the wire color changing to L-W, at a splice?, but my diagram shows no change in the wire color).

I don't understand why you would want your ECU involved in turning the A/C on and off, but that's up to you. Just keep in mind that you have to keep it from powering the A/C Amplifier when the heater relay is open.

 

I need the ECU to know the ac is on so it can control the idle air control and cooling fans properly

The factory Toyota A/C amplifier is completely self-contained and handles pressure switches, evaporator freezing, and compressor cutout. The Haltech’s job is simply to recognize when A/C is requested so it can raise your idle and cut the compressor at full throttle.

• Idle Up: The Haltech automatically increases your target idle RPM and/or idle valve duty cycle the moment the A/C is activated, preventing the engine from bogging down or stalling.
• WOT Cutoff: You can program the ECU to disable the A/C compressor clutch when the throttle is wide open (WOT) or during high engine load, restoring power to the wheels and protecting the compressor.
• Safety Lockouts: You can set the ECU to disable the A/C if the engine begins to overheat, or if the RPMs go too high.

would you be able to post your diagram? I’ve been having a hard time finding accurate diagrams for a 94 pickup 5 speed 4wd 22re

 

I'd probably be talking to Haltech or a dealer about wiring the ecu to know when idle needs bumping.

 

the post above this states the instructions and function of what I’m trying to do from haltech.

 

Could you just tap into the AC clutch wire for signal?

 

the haltech uses ground to complete relay circuits to turn things on so I need to locate the A/C clutch relay power from dash switch and relay ground. But I can’t find any good diagrams, the one I posted doesn’t have the same colors as my truck