All of the sudden, my ac clutch wont engage. I pulled the plug to it, and with the ac on, I have 12v going to the clutch so I know everything leading up to the clutch is working. I can freely turn it by hand when the truck is off. Am I correct that the clutch is shot? And do I have to (or should I) buy a whole new compressor, or will the $80 clutch on ebay fix the problem for me?

 

Check and see if the ground for the clutch is good. If it is, then yeah, just the clutch should do ya.

 

Just to follow up with a solution:

I pulled the clutch, bearings were good, coil magnetized nicely. So, I took out a shim under the front friction plate and reinstalled everything, and bam - it engages and a/c works like it should.


For anyone else who has to take off the clutch, heres how I did it without using any fancy tools:

--First make sure that you have 12v going to the clutch with the ac on, if not, there could be a wiring problem or a pressure switch is open. Try adding more refrigerant and checking the high and low pressure switches with a multimeter. If there is power to the clutch and it doesn't engage, or you know your bearings are bad, proceed:

*For removal and installation, removing the fan shroud will make things a lot easier, but its not necessary.

1. Remove 14mm (I think) bolt on front of the clutch. You need to keep the front plate from moving by inserting something into at least 2 of the 3 holes that are around the bolt. They do sell a tool for this, but I just used a wrench from my grinder and it fit perfectly.

2. With the bolt off, pull off the front friction plate (you may need to persuade it off with a screwdriver), being careful not to loose the shims (thin washers) beneath it.

3. Remove the snap ring that locks the pulley in.

4. The next step of removing the pulley and bearings is the hardest. There is a specialty toolset, kit 6460, that I think costs around $275. If you are on a budget like me, you can use a jaw puller to remove it, or CAREFULLY use a crowbar and hammer. Make sure you are attaching onto/knocking the pulley only and not the electromagnetic coil behind it.

5. Once that gets worked off, remove the snap ring that holds on the coil and the coil should slide right off (don't forget to unplug it).

The coil should magnetize with 12v attached . If it does activate (test by placing a screwdriver on it while plugged in), you may need to leave out a shim from step 2. BE CAREFUL if you undo the shrink tubing on the wiring, there is a diode in there (1N4007) that protects against the energy spike when power is cut off from the coil. If you break it its like $3 for a pack of 15 at radioshack, make sure to connect it in reverse with the side that has the white line on it connected to the positive wire.

6. Reinstall going in reverse. To press the pulley back on, I attached 2 2x4s together and drilled out a hole for the shaft to fit into so no pressure is put on it. Then I just pounded it on with a heavy hammer, staying towards the center.

If the front plate touches against the pulley without the clutch activated, you took out too many shims. If the coil activates but the plate wont hit the pulley, you need another shim. There is a guy on ebay that sells the individual parts as well as a full clutch kit for $80, which sure beats a new compressor and clutch and having to evacuate, vacuum, and recharge the system.

 

ok after several trips to internet and supposed experts i traced 12v like many others to the wire before clutch and found no 12v and like many others jumped the clutch and it energized with power from batt
tracing wire back to compressor just on the back side of compressor is what appears to be a round black disc that wires go in and then exit to a harness and then to a plug -i found i had 12v on this side -the plug i mention has the vener diode enmbedded within -so here is the deal cut the wire below diode as close to compressor and splice thee 2 blue wires together -ac will now work the disk is a thermal protection device not found on diagrams-
solution was told to me by certified ac repairman with 30 yrs experience-when asked if this will burn clutch out hot wired ans. was no because this connection is past all relays and cycle switches all you are bypassing is a thermal protection switch in compressor and at that point you would need to replace anyway if it froze up due to overheating
this is on a 2000 dodge ram1500 van
hope this helps someone else

 

AC works perfect. Clutch will engage with a little help. By giving a light tap while engine is running(very carefully) the clutch will engage, AC will operate fine until it recycles and needs the clutch needs to be engaged again. Perhaps needs to be given a good cleaning and lub? Any ideas?

 

Replace the a/c clutch.

 

A weak coil or too much space in the clutch for the coil to compensate for.

 

The clearance between the clutch disc and the pulley have increased from wear. Just remove 1 shim from between the clutch and pulley. The shim is a thin washer. To do this first mark the allignment with a sharpie of the clutch and pulley to put them back exactly as it came off.
Remove the center nut.
Pull the clutch off, watch for the shims so they don't fall off.
Remove only 1 shim and reinstall clutch.
If it doesn't work remove another shim and try again. Repeat this step again if necessary.
If it still doesn't work after removing 2 or 3 shims, replace clutch. You'll get to play the shim game all over again.