I want to refill with freon my 94 Toyota Corolla but I can not find the low pressure port, I only see the High pressure port. Do you know where is the Low Pressure Port located so I can refill my car with freon the summer is coming and the weather ig getting hoter every day.

That's a sign that your system is very low of refrigerant. So it's best to find and fix the leak before refilling. Adding refrigerant on a system that's low and leaking is a really bad idea. See these two posts about how to diagnose a compressor clutch that won't engage and how to recharge http://ricksfreeautorepairadvice.com/ac-compressor-clutch-not-engaging/
http://ricksfreeautorepairadvice.com/ac-recharge-on-your-car-or-truck

You are probably low on Freon. Your symptoms are the way the A/C goes out after running out. A bigger problem is losing the lubricating oil in the A/C system as the compressor can seize if the safety pressure switches fail.

There are several fixes and approaches to each problem. You need to determine if Freon still exists in the unit. You can get by with adding Freon with an additive to fix leaks and lubricate the compressor. To add Freon you need to access the Low pressure port and jump the Low pressure safety switch for the initial can of Freon.

There are tool loaner programs at the big Autoparts stores which can allow for this process.

These same stores may have electric Vacuum pumps to purge your empty system for refill. If you do not have enough pressure left in your system, outside air can enter. If you are lucky and timely, a refill with Sealant Freon mix after purging the system can restore it.

Every car is a different case. As your car is 10 years old, it may have been leaking slowly for years, or in the last week. You never know until you try finding the leak. Some people just spring forward and trust the Sealant to work. Others use devices known as sniffers or leak detectors before trying to refill the system. Some leaks can be so small or in places with no visual access.

The cheapest way is to use the Sealant Freon after testing the pressure. Use gauges to determine system pressure.

Please comment on my info.

First of all check the freon pressure, if the pressure is low the compressor clutch will not turn on. The pressure should be between 30-40 PSI.

THE LOW PRESSURE LINE IS ALMOST ALWAYS LOCATED ON THE WIDER PIPE OF THE 2 AND SOMETIMES THEY HIDE IT UNDER THE AIR CLEANER ASSEMBLY.

You have to locate the low pressure line and connector port. Trace the two lines back to the firewall that come from the compressor. You will find 1 port on each line. They are usually covered by a plastic cap of some type that unscrews. Your refill hose, assuming you have a standard refill can with attached gauge, will only attached to the low pressure side. The two ports are slightly different in size. The low pressure side should be the larger of the two lines you are tracing from the compressor.

The Low Pressure Side connector will be smaller than the High Pressure Side connector so the refill hose will fit properly only on the Low Pressure Side.
Read more: How to Recharge Air Conditioning with Freon in a Dodge Ram | eHow.com http://www.ehow.com/how_4484569_recharge-air-conditioning-freon-dodge.html#ixzz0uLCDkUE8

Did you check the pressure of the freon? Mine was doing that. The pressure was fine but wouldnt start. It was the low limit switch on the low pressure side. Right above where you hook the freon up. Unplug it and cross the plug out with a jumper wire while its running and ac is on.
And see if it kicks on. If not then maybee fuse or relay? Or could be low pressure.

It should have a low freon pressure switch.This may be worn or the system has low freon and this switch is over rideing the power the compressor clutch.

The smaller pipe, usually the cap is blue, that's the low pressure side.

no but u can find them by following the large ac line/hose and the low side port will be the small one follow the small ac line/hose and the high side will be the larger of the two