I am trying to locate the low pressure port on the air conditioning system in order to retrofit it with 134a. There is no port up by the firewall as I have seen elsewhere on the web. Perhaps it's on the back of the compressor? Can anyone tell me it's location?

 

I’m looking for the exact thing! Good luck. I’m going to keep this thread open to hopefully get an answer if/when you do

 

I am trying to locate the low pressure port on the air conditioning system in order to retrofit it with 134a

This is the location on my 84-XJ6
Rgds
David



Low pressure fitting on back of compressor

 

Hi David, Thanks for the pic. Problem is that there are two connectors on mine right where the arrow is. The two fill connectors are inches from each other.

Is the low side fill the one that comes off the fuel cooler --> hard line right to the back of the compressor or the other one?

 

Yes, the low side line should come from the evaporator, through the fuel cooler, to the compressor suction side. The high side line should go to the condenser.

 

Here is a nice clear generic car air conditioner schematic showing the high side port and the low side port.

 

If you look at compressor from rear, then the low pressure fitting is the one on the left.

Rgds David

 

The R134a Low Pressure filling fitting is screwed on to original R12 fitting with schrader valve removed --use sealant recommended). I used a Four-Seasons HLPS switch screwed on to original R12 high pressure port (New R12 schrader valve, allows for switch removal with out loosing pressure) --use sealant recommended). Since Switch was close to Exhaust, I wrapped switch with Heat Protection. Another option: (I could have purchased 12 inch high pressure line and mounted HLPS remotely.) Switch provides ground to Compressor clutch ... low pressure no ground.... high pressure no ground....correct operating pressure, clutch has a ground . Deletes the original Super Heat Switch harness and parts. Fabricate your own wiring harness with ground wire from switch going to mount bolt on compressor. Just leave original low pressure switch in back of Compressor. All servicing done through low pressure quick disconnect fitting.
Rgds
David

Rgds
David


R134a Low Pressure fill fitting

R134a High pressure HLPS switch