Automotive Air Conditioning Information Forum

Been working on the 1992 Buick r12 AC for over 2 months now - I have studied the charging procedure over and over - every single piece of hardware is new - held great vacuum . Did all my pre-checks....Today was the big day to finally charge and then ...flop..

With the car off, I charged one 12oz. R12 can as a liquid on the High side (HR6 Compressor). no problem there. Turned off the high side valve and then connected 2nd can to the Low. Turned the car on - Compressor started cycling. It seems that as soon as I open the Low side valve for the 2nd R12 can to flow in , its stops cycling and then both pressures slowly climb/equalize at 110psi - its about a 100deg. here in Dallas. ..Even though I put the can in hot water - upright- seems like no more gas is flowing , compressor is doing nothing and gauges are equalized at 110...I tried to jump the Low Pressure Cutoff switch just to see if the clutch would engage - but nothing happened.

hope someone can assist..thanks

By any chance is your lo0w side hose fitting not opening the low side shrader?

Yes....

thank you

You don't "jump" the switch, you jump the connector to the switch....If a/c compressor does not come on when doing this, then you have another issue- such as a relay, or high pressure switch unplugged, or a power steering switch unplugged- get a wiring diagram of your a/c circuit and do the diagnosis of it.

You are posting on a 5-year old thread that the OP never came back to