My ac system does not work the compressor clutch does not engage when I turn it on my pcm went out and I would like to know how to test the ac compressor and where the cycling switch is and what does the pcm do to the compressor the system is holding pressure the compressor is just not cycling I don’t know how much pressure is in the system if that’s the reason why it won’t engage I’m not sure

 

The A/C is one of the things the PCM is in charge of.
Along with charging, wait to start, cruise control, grid heaters and O/D if you have an auto rig.

I can not remember your trucks specifics and you have not filled out your trucks details for other people to see. That would help us, help you.

 

I got it filled out for ya

 

Strange, as I do not see anything.

 

I will just tell you bc I’m not sure how to do it than it’s a 91.5 single cab red auto a518 O/D works with a pressure switch the ve pump is cranked otherwise stock motor antilock brakes deleted grid heaters not hooked up yet no cruise control crank windows no power lock

 

Since you have a 91.5 you still have a VR on the firewall, so it still charges without a working PCM, which is a major bonus.

 

The VR was going out all the time so I bought a pa performance alternator and changed it and never looked back best thing I did to the truck besides tuning the pump

 

Where can I get ac hoses I looked on rock auto and all they sold was non intercooled hoses and can anybody please show a picture of where the ac cycling switch is I was reading about it and they said you can jump it to see if the compressor is bad

 

I have working, OEM A/C lines and parts saved from trucks I have worked on in my shop.

 

Yes I figured but doesn’t r-134a need barrier hose to not leak out

 

I took my lines to an A/C shop in Tulsa OK and they used my ends with new rubber. They have been fine for years. No leaks with R-134a. However I found some reclaimed R-12 on Amazon or Ebay and I am going to convert back since the R-134a doesn't cool very well.

Edwin

 

I got a case of 11 R12's couple of years ago at Nashville Mopar show. $200-ish (?)