Where is the A/C charging port on the 1994 RT/10

The 1994 Viper was built without an A/C option , but the vehicle was built with all the component attacment point, the wire harness, the selector switch and the evaporator in the HVAC unit. you just had to buy the production install kit, which was the additional production parts sold on the later year vehicle. if this kit was used then the high pressure tap would be near the reciever drier bottle located on the P/Side of the toe box in the engine compartment. Next to it would be the large suction line which had the low pressure tap where the A134 refrigerant would be added. if it was an aftermarket system then look for a tap somewhere on the suction line or compressor. good luck.