autocomman

SO i know EFI live and HP tuners will change the a/c request from serial data to a straight 12v+ signal, but what pin do I use then to wire it up? I wouldn't think I could use the serial data line. ive got a 2003 ECU, so i go by the earlier diagrams for A/C request?

Mark

69 Ghost

There are 2 different setups. One for the fixed compressor and one for a variable. If you are using the fixed use the wiring diagram for a truck/express van. This is wired with a pressure switch and cycles the compressor. If you are using a variable you need to wire it with a pressure sensor and wire it like a Camaro/Vette. Pinouts are different and there is a program setting for A/C type.

autocomman

Ok, im using the old school R4 compressor on teh car so change it to 12v for the enable type and fixed for the compressor type, wire according to a 2003 van..sound right?

69 Ghost

That will do it....

BP Automotive

iTrader: (3)

Just as a heads up we can make any blue green use the camaro/firebird hard wired a/c request and pressure switch. This is by far the best way to run your a/c.

Bill

autocomman

I dont need the pressure switch, this most likely wont have electric fans, just a mech fan, and it's already got the factory cycling switch thats run the system for 32 years with no issues, even after the 134a upgrade, i still get sub 40 temps after a small initial adjustment of the switch. If I do add an electric fan ill look into the alternate wiring. Right now though I just wanted to have the PCM control the compressor via the cycling switch

bigmandengo

iTrader: (21)

Which tuning software do you use to accomplish this? Also, which operating system are you running to achieve a 12v request and use the pressure sensor to operate ac and electric fans?

I have hptuners and I see with their new software update you can change the ac type. I haven't heard of any real world experience on whether or not you can make the 12v request work with the pressure sensor. The only calibration that I know of that uses a 12v request is the full size vans and they don't use the pressure sensor, they use a cycling switch.

Jesus Freak

Im curious about this as well. I have a GMPP E67 in my swap and am working on AC. It'd be a lot easier to have the PCM control the clutch than the system I have laid out.

69 Ghost

I'm using a 04 GTO OS and a 802 PCM to run a pressure sensor and a variable compressor hooked to a vintage air on a 4th gen harness. The problem here is people look at one year wiring and/or vehicle and don't see the wiring and you say it cannot work. Think of it this way the newer PCM's are just updates of the 411. Wire it like a 411 and setup the OS for the A/C type along with the differences in the wiring and it will work.