Hello, I am new to this forum as of this morning and need some advice. I purchased a 2001 F150 and the ac doesn't work. The r134 level is good and there is current going to the compressor at least from the wire coming out of the top canister where the ac is charged. I can turn the clutch freely with my hand and the clutch fuse is good but does not work when the ac is on. Does it sound like the whole compressor needs to be replaced? Can I just replace the clutch or could there be an internal switch that has gone bad?

 

How did you check the R134 to know it was OK when the clutch doesn't work? Is it an XL,STX,XLT or Lariat? Jump juice directly to the compressor at the plug on the compressor. Jump directly from the battery. Make sure the compressor has good ground (Don't know how it could not, but I never assume because assumptions are often wrong). If the compressor doesn't work then, the clutch is probably bad, but they seldom go bad. You can replace the clutch without replacing the compressor, but I would make sure the compressor turns freely before replacing the clutch, if needed, you don't want to find out after replacing the clutch, that the compressor is locked up! I believe you would be able to put a socket and ratchet on the nut on the end of the compressor shaft to turn the compressor.

 

I assume you cannot see the clutch turning. Sometimes the gap in the clutch gets to be to big to pull in the clutch (from wear). In this case, there are shims that can be removed to close the gap. Do a search, there is alot of info on here with explosion diagrams, so you can see what I am talking about.

 

Follow the wire from the compressor back to the pressure switch. Pull the connector and jump the wires. Then have someone turn on the A/C while you look to see if the compressor starts turning. Don't run it for a long time, a few seconds is sufficient to see if the clutch kicks in and the compressor turns.

If it kicks in and turns, you are probably just low on R134a refrigerant. You need gages on low and high side to charge it properly. The pressure switch is doing its job correctly.

If it does not kick in and turn the compressor, then check if you have voltage at the supply side of pressure switch. If you do, then your pressure switch is bad or your compressor clutch is not working. If no voltage at the switch connector, then you have to figure out why no voltage. Keep following the wire back until you figure out why.

The pressure switch can be changed out easy, the compressor clutch is a much bigger job. Both should be able to do without opening up the system and losing charge. Pressure switch you can do with standard tools, clutch requires special tools.