I searched a few places but get more clutter than answers on this...

I'm swapping a 2005 5.3 motor into my 1952 chevy and I'm going to be using the Holley Belt Drive brackets and Stock PCM. In the Holley instructions it says to wire a window switch to ensure the A/C compressor does not activate above 4000 RPM to prevent damage.

My question is:

If I plan on using the OEM A/C Clutch control output from the PCM, would I still require a window switch? Or does the PCM automatically cut the A/C Clutch over a certain RPM already?

Thanks in Advance

 

It will auto cut the ac clutch when it hits a set rpm. However to use the ac system, you need to wire in all the pressure switches and things to make the stock pcm work for it all correctly.

 

OK. I figured I would have to wire in the Pressure switches.

But it also looks like the A/C "On" Signal is sent via Class 2 Serial Data to the PCM. Does anyone know a way to make a standard discrete wire connection to tell the PCM to kick on A/C?

 

It is possible to do but not all 1 meg PCM.s support it

 

Stock PCM has full control over the A/C compressor.
To enable a standar 12V signal for the A/C request (instead of class 2) you need to change it with Tunercats or Jet DST. HPTuners currently doesn't have access to change it.
There are more parameters to be modified, but id works good. I have installed a few swaps with A/C and no problems. You just need to make sure wiring is correct and PCM tune is also correct for the compressor type you have (fixed or variable displacement). You'll need the low and high pressure sensors depending on the setup

 

What year platform and svc number of pcm are you using