Low side AC port

if you have to charge the ac every year then you really need to get the leak fixed, take it to a shop and have them diagnose it to find the leak and what needs to be replaced. if you don't the leak will get worse every year. as of the blower problem, that would be the resistor, replace it and all the fan speeds will work.

where is the low pressure A/C side?

Just follow the large ac line from the firewall to the compressor It will be somewhere on there.

Here is a video and guide to help you

https://youtu.be/ON2dYcmXIAw

and

https://www.2carpros.com/articles/air-conditioner-how-to-add-freon

The low pressure charging valve is located either on the accumulator or low pressure line.

Closest I can come up with is a 92 W body Oldsmobile cutlass supreme. It doesn't differentiate 3.1 or 3.4. The accumulator is in the lower left front. The low side fitting is shown on the low side line from the accumulator to the evaporator, and the high side fitting is shown close to it. I would say if it is not in that line, it is in the accumulator, or the suction(low side) line at the back of the compressor. If there is a low pressure cycling switch on the accumulator, you may be able to remove it and use that port, just jumper the electrical terminals to close the circuit for compressor operation

I have a problem. My car air conditioning goes off, the fan goes off also, when i am driving uphill. It only happens when I'm going uphill and also around a real sharp curve ; ie. an exit ramp curve. What is the problem with my car and what service do I need you to do?

Hi,The Way I'd Check This One Make Sure Car Is Not Low On Freon First. If That Was ok I"d Check The Pressure Switches, If they Were Ok, I'd Check The Wiring To The Ac Compressor and Fans.On Some GM Models The Wiring To The Ac Compressor Goes Under The Radiator Support. It Can Get Damaged Over Time From Parking To Close To The concrete Barriers In the Parking Lot Causing And Bad Connection At Times.And Finally Was car Ever In A Front End Collision? Could Have Wiring Problems? Without Seeing The Car ,Would Be A Guess.

Hopes This Helps You,
Good Luck

Edward S.

I am looking to re-charge my A/C with commercial off-the-shelf refrigerant, but cannot find any identifying marks on the high and low pressure lines.

I have been told that the low pressure line is always the larger tube. Is this true? Also, this model (GTP) car is new to me and it does not seem to have the same type valves (for filling) that I am used to seeing. (air valve type) Are these a special type of valve

and will commercial filler type refrigerants with the attached hose work?

yes the low side is the fatter tube and you can buy refrigerant at parts store with a gauge and hose for cheap money.