The low side service valve is located in the line that runs from the compressor through the evaporator (firewall) and up to the condensor on the low pressure (suction) side of the system. R-134a Recharge hoses will only fit on the low side service port on all R1-34a vehicles and R-12 vehicles that have been converted to R-134a. If you don’t know where your low side port is you can try using our low side port finder.
The only fitting that the standard recharge equipment will fit is the low side service port.
You can view images of typical low side port locations here.