I Have a 2000 Expedition 5.4, atempted to charge the ac. I was getting a preasure reading but no freon would go into the system. When the compesor cicks on i get a reading of about 30 psi when it goes off it drops to 20 psi and it blows warm air.

add R134a freon and use a fill hose with a gage and keep in safe range. Keep can upright to fill system as a gas. Inverting will send a flood of liquid freon in - not good.
Can you hear the a/c clutch engage and disengage a few times/minute?

There is no reset, check the fuses, if the compressor is not working ,it may be due to low freon in the system, there are switches that shut compressor down when freon is low, this avoids compressor damage. the first thing to do is check to make sure the system has a full charge, if its low then recharge to correct amount and add dye this is dangerous system under high preasure, let a ac tech check the system for you. hope this helps.

The first thing to check is to make sure the ac system is fully charged, low freon will cause this to happen, so start by having the system charge checked.

hi, the freon refill point you are looking for is on the accumulator. but you can't see it cause it's buried by the heater hoses, battery cables, and firewall mounted fuseblock. remove the fuse block cover, and get a bright flashlight, look just below the fuse block and you will see the cylindrical accumulator(aluminum canister looking) and the low side pressure port with the plastic cap on it.

Under the hood is the Heater Control valve need replacing.

Does it have the correct amount of freon, it can still blow cold with the wrong amout of freon, this will damage the compressor,you may also have a bad cycling switch or bad high preasure switch and even a bad connection to ac system,this first thing is to make sure the correct amount was installed,

yes, but your ac system contains switches, one low preasure switch to shut compressor down when freon is low, this is to avoid compressor damage,if low on freon the compressor will not turn on. the first thing to do is make sure the feron is full, you will need a teck to do this, i dont think you should atempt this, its high preasure you may cant hurt or damage your system if not done right.

You do not have a cabin filter....Two things......you need to check (freon preasure) you may have a freon leak from the AC evap coil behind the instrrment panel,the smell is AC freon pag oil from the AC system, it smells funny. Or you may have mildew build up on your evap coil there is a spray to disinfect the coil.Check auto zone or pep boys....Good luck my friend

Do you have gages you can hook up?check preasure when A/C clutch is on preasure low should be about 30 and high should be about 180,if high side is higher you got a blockage some where usealy they will plug at the recever dryer or the expansion valve

Hi .. I just ran into the same problem .. I have a 2000 Expedition with the 5.4L engine .. the low side port is located on the passenger side of engine compartment just below the black metal bracket that contains electrical connections right in front of the firewall... you have to reach under this and locate the low side (larger line) and feel for the connection .. it is right in front of the accumulator .. There are two heater hose that hide the port .. you have reach under these to unscrew the port cap which is black .. you'll have to do this by feel .. I have found that you can by R134A charge with dye and leak sealant helps with small leaks .. if the system takes more than two cans be usre to add refrig. oil .. hope this helps