I know most of you know this-help me out-please!

I'm trying to recharge my A/C with a kit (R134a) and can't find the low port(s) to use for filling the system. I've checked and filled the upper port (compressor) and it's at 45psi. There's still no cool air from the vents.

I don't see any other ports when I'm looking down into the engine. Is it possible that they need to be accessed from underneath? Thanks - I'm just learning to take care of some maintenance myself!

Does the compressor turn on when you switch the ac on?

yes - when the engine is ideling it cycles on & off every few seconds - & obviously changes the pressure reading whenever it does.

I'm beginning to think I've been testing & filling with the port on the accumulator (silver can-like part). If I'm reading other posts correctly this would be the low side port. My next question - then where's the high side port???

Obviously my career is not in the auto techician field!!

Thanks for any hints/help.

My 98 Blazer has no high side port. Maybe yours is the same (you didn't say what Blazer you have). I have to recycle and recharge R134a through the low side, and most recharge systems don't like that at all - have to force them to charge over and over until it's full (and it keeps saying "error - charging has slowed" every few minutes). My 86 IROC Z-28 Camaro is the same - no high side port.

All kits I have seen say not to charge through the high side, by the way. If you had put a kit (with little bottle) on the high port, you could have blown your hand off when the bottle was over-pressurized. :disappoin

My 98 Blazer has no high side port. Maybe yours is the same (you didn't say what Blazer you have). I have to recycle and recharge R134a through the low side, and most recharge systems don't like that at all - have to force them to charge over and over until it's full (and it keeps saying "error - charging has slowed" every few minutes). My 86 IROC Z-28 Camaro is the same - no high side port.

All kits I have seen say not to charge through the high side, by the way. If you had put a kit (with little bottle) on the high port, you could have blown your hand off when the bottle was over-pressurized. :disappoin
Your blazer has a high side port. It is below the accumulator, in the line that goes from the condensor to the evaporator.

I'm beginning to think I've been testing & filling with the port on the accumulator (silver can-like part). If I'm reading other posts correctly this would be the low side port. My next question - then where's the high side port???

Obviously my career is not in the auto techician field!!

Thanks for any hints/help.

Yes that is the low side port, you are doing it right. Don't ever try to fill on the high side port. With the compressor off, you should see high pressure. With the compressor running, the pressure will drop. You want the compressor running the whole time you are testing and filling the system. Pull the wiring connector going to the accumulator and jumper the two wires together if the compressor won't stay running. Fill the system until the pressure is about 35-40psi.