1991 Chevrolet G Series Van (G20) Q&A
1991 Chevrolet G Series Van (G20) Question: which one of service port to fill refrigerant in my van?
The high side port is a different size than the low side fill port, so the freon adapter will only fit the low side. Take the caps off and see which one it fits. - lightsaber
Agree with answer 1! Blue is the low side or charging port on the accumulator. ("canister") - pushrod