Hope I can help you. I don't have a diagram, but I can tell you that the larger fitting is the high side and the smaller fitting is the low side.
Hope this helps.....
How are you? If you will look at your a/c compressor where the lines come out you will have 2 lines. One big line and one smaller line. The bigger line is your low side and the smaller line is your high side. If you follow these lines you will see a fitting to hook to. The low side fitting should have a blue cap on it, and the high side line should have a red cap on it. You want to fill thru the low side. If you have a can of R134 and a hose it will only fit on the low side connector. Make sure you do not put to much freon in it. A/C system has to have close to the exact amount of freon that it calls for to perform correctly. If you overcharge one it will not cool. If you undercharge it, it will not cool. It is best if you have a set of guages to be able to read your pressures.
You will only have 2 connectors you can hook to. One low and one high.
Hope this helps...