Below are some pictures of adding refrigerant to a 2000 crown victoria.

This car recently had some air conditioning system service work done and it is completely empty of refrigerant. Factory specifications call for 38oz of r134a refrigerant, but 3 12oz cans of r134a should be sufficent to get the system working again.

Here's an empty refrigerant can with charging hose attached for illustration purposes

Notice the hole pierced in the top of the can from the can tap.

The charge port on the 1992-2002 crownvics is on the low side suction accumulator.

Although not shown, I usually boil a plastic container of water in the microwave and partially submerge the can of r134a refrigerant in the water during the recharge procedure. This helps get all the refrigerant out of the can during the recharge. It's obvious that there is heat transfer going on because the hot water will become cold to the touch when the refrigerant can becomes empty.

Be warned that the can of refrigerant will become very cold as the car's a/c system is being recharged. So you will want to wear a thick set of insulated winter gloves to prevent your skin from getting frostbite.

The a/c system is currently under 29mm of vacuum, so the a/c cycle switch is going to have to be jumpered to get the compressor clutch to enagage.

You might want to use something other than an exposed bent paperclip to jumper the a/c cycle switch in case it accidentally contacts the metal chassis of the car

Now that the 3 cans of refrigerant have been added, a manifold guage set is connected to the system.

The accumulator is sweating nicely from condensing water in the ambient air

The metal end of the suction hose near the compressor is also sweating from condensing water from the ambient air.

When service guage connector was removed from the accumulator, some refrigerant and oil escaped. Ford uses factory green tracer dye in their a/c systems that you can see below. Looks almost like antifreeze at a quick glance.

The r134a refrigerant fill procedure was successful and the air conditioning system in the car now blows cold. However, the highside head pressure was 310 psi on a 75 degree day. But this reading fell to 250psi on a 80 degree day after cleaning debris from the condensor and evaporator with water from a garden hose. The discharge readings are still a little high, but not so high that the refrigerant lubricants will break down in the relatively mild ambient temperatures of a northeastern united states summer.

After the refill, there was ice sometimes forming on the outside of the evaporator and accumulator. This shows that compressor is creating a good pressure differential between the suction and discharge ports, but unfortunately minimal air flows through an evaporator that has turned into a solid chunk of ice. So a new aftermarket four seasons low pressure cutoff switch was installed, and the ice has disappeared for the most part. The new switch cuts the compressor out at a slightly higher pressure on the low end, and leaves the compressor disengaged until the pressure builds to a slightly higher pressure than the old switch did.

The a/c system now seemed to be working good when taking short trips around town with mild ambient temperatures. When a longer trip was taken on the highway during 90 degree weather, the a/c system started to blow warm air though. Further investigation revealed cracks in the rubber insulators on the front compressor clutch  plate and some discoloration of the compressor clutch metal from high heat. These symptoms pointed to a clutch that was slipping during high load conditions. So a shim washer was removed from the clutch and the clutch seemed to be holding good during high load conditions. Some surface wear of the clutch plates is normal on older cars. However, if so much heat is generated during clutch slippage that the grease boils out of the clutch bearing, then a new compressor will need to be installed.

Finally, the a/c system seems to work acceptably. The car could use a new compressor due to clutch wear and a slight shaft seal leak. The condensor is somewhat corroded from being blasted with chloride road salts and sand during the winter months causing reduced heat transfer capabilities. The two hoses that connect to the condensor have visible corrosion around the connection points to the condensor, though the connection points don't seem to leak noticeable amounts of refigerant at the moment. The electric condensor/radiator fan seems to be spinning a little slower than the 1998 crownvic that has a new fan motor installed. However, the a/c blows cold and the car can likely be driven for a while without replacing any additional parts in the near future. This is not a new car that just rolled off the dealership's showroom floor yesterday, but rather a ~10 year old car that has been driven over 100k miles. Also, the car lives in the northeast where ambient temperatures during the summer are relatively mild compared to much of the country.