How much freon does a 97 jimmy hold - 1997 GMC Jimmy

It depends on which engine and which AC system is installed, some hold as little as only 8oz., some as much as 55oz. or more. you could start with around 20psi, that's if your using a refill kit with a recharge gauge that's measured in P.S.I.'s!. Add freon while the engine is running and warmed up to full operating temp, fill through the LOW pressure port only (your refill hose adapter shouldn't fit on the high side anyway), and with the AC system turned ON, if it feels cold (35f-45f-50f with a thermometer) and your compressor clutch is spinning and isn't slugged (spinning and than not spinning than spinning again while turned on) your good, if its not cold enough keep adding by 5psi increments till you get to around 35psi to 40psi. If your slugged just let some pressure back out slowly the same way you would let air out of a tire, but don't use your finger, carefully use a long screwdriver.