I'm looking to run a toggle switch for "high idle" that will tell the PCM that the A/C is on(not currently running A/C). I have read that it will not work without pressure sensors and I've also read that it may be possible to wire up resistors but the instructions were unclear. I have an LQ4, harness, and underhood fuse block from a 2003 Chevrolet Express. Donor vehicle is a Square Body car carrier. I understand I'm not inventing the wheel here and a link to the answer would be greatly appreciated!!
Eric