R12 Charging Problem

[robmaxfli]

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

[Dougflas]

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

[robmaxfli]

Yes....

thank you

[GM Tech]

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.

[tbirdtbird]

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