Can I connect the High Side hose from the manifold gauge to one of the ports in the condenser swiches? I try the remove the cap in the back of the compressor, but I felt air pushing out.

Thanks for info. The cars use R134a refrigerant and one is a retrofit, so they have the low side fitting for the charge coupling near the accumulator. The problem is that I bought a manifold gauge that has a sight glass and I was wondering how on earth I was going to see the refrigerant if is can't go through the manifold...and that will be another post in a minute, because I also wonder if it is OK to by pass refrigerant from high side to low side trough the manifold.

hardknocks! is right, there is not a high pressure valve. Fill by weight from a vacuum, or as I do when I have to top off the R134, by low side pressure and compressor cycling. Lots of information in the FAQ.

hello
i removed the condenser switches at the JY as i wondered the same thing? they screw on and one would probably have to fab up a special connection?
i do not know.
i believe there is no factory connection for the high side guage and been told they fill the system by a pre-determined amount of freon.
not much help i am afraid.
let us know if you figure it out.
good luck
mike