AC Compressor Upgrade
 

I am upgrading my AC to a Sanden compressor and I was wondering where would I install the high pressure cycle switch. The stock location was on the back of the compressor. Would I tee it into the high side output line? If so, what fittings would I use and what switch would work?

Terry

Re: AC Compressor Upgrade
 

The HP sw isn't really a "cycle" thing. Strictly an over-pressure safety cutoff.

Most systems don't have one. In fact not even all of the ones in these cars do. I wouldn't worry too much about shadetree-engineering one in if there's not already a built-in spot for it.

Re: AC Compressor Upgrade
 

My wife's 1987 uses a high pressure cutout switch but my 1985 just uses a high pressure valve that dumps excess pressure down to safe levels. I bought a sanden style and haven't installed it yet but it appears to have a high pressure valve built in already.

Re: AC Compressor Upgrade
 

I don't think there is any high pressure switch built into my compressor, Sanden SD7. There is only one wire coming out from the clutch. I did figure out what I will do. I found a fitting that includes a binary switch that controls low and high pressure. It installs on the high side. The wire looks like it will plug right into a Sanden compressor.

Re: AC Compressor Upgrade
 

I tried to attach a picture but it didn't work. I found this on both this site and ebay.


https://coldhose.com/switches/oring-...d-pigtail.html

Re: AC Compressor Upgrade
 

Sofakindom already gave you the answer you need. The switch on the back of the R4
compressor is a OVER pressure switch. It opens its contact if the A/C line pressure
exceeds a certain (dangerous high) PSI. It has nothing to do with the A/C clutch cycling,
The actual pressure cycling switch is located on the dryer (big silver can outside the blower box).

The Sanden compresser just has a high pressure relief valve,
no switch needed. No extra wiring/engineering involved or needed.

The now defunct plug just needs a jumper in to make the system work again.