which one of service port to fill refrigerant in my van?
on 1991 Chevrolet G Series Van (G20)

one with blue cap attached to the canister and orange cap attach to the pipe going lower part of the canister? Pleased advice, thank you in advance! Omie.

Asked by for the 1991 Chevrolet G Series Van (G20)
Agree with answer 1! Blue is the low side or charging port on the accumulator. ("canister")
Thank you so much!

Lightsaber and Pushrod,

Thanks pal I made it, it was so easy appreciate you're help.

Again thanks to both of you.

Sure thing.
1 more answer , 2 more comments
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.
thank you very much!
You are very welcome, and Thank You for the feed back response!