Can someone tell me where is AC low port
 

Please check pic. and let me know where is low port of AC

there are two ports on that aluminum and one another in line ...so total 3 that is why am mostly confused...

Re: Can someone tell me where is AC low port
 

I've never seen an accumulator with two ports on it, the low side will be on the accumulator, I'm guessing either one will work. Are they both the same shape when you take the cap off? What year vehicle? If it is an R134a system the low port will be a smaller diameter than the high side port.

Re: Can someone tell me where is AC low port
 

Vehicle year is 1989 gmc s15 2.5 liter engine automatic

It is not r134a its r12 system and under those 2 caps on accumulator both ports are same size but the third port which is one line (not on accumulator) is smaller than these two...

I have to use adapter kit in order to put r134a in it..

Re: Can someone tell me where is AC low port
 

The low ports are on the accumulator(aluminum canister), either one will work then. The high side port is the smaller fitting on the line. Be sure to change your seals as well when converting over to r134a.