V-10 A/C compressor doesn't engage

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Mar 9, 2009 | 11:30 AM

mdcyr

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V-10 A/C compressor doesn't engage

The A/C on my 06 F250SD V-10 stopped working abruptly. The clutch is not engaging. Checked fuse and relay . . . not the problem. Tried disconnecting the low pressure switch and jumpering the leads but that didn't get the clutch to engage. The clutch does not look like it got hot, turns freely, and was not making any noise leading up to the problem. Truck has 35K miles. Any ideas?

Mar 10, 2009 | 08:01 AM

wickymustang

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Have you left everything hooked up, turned on the AC and back probed the wires at the clutch to see if the command is making it to the clutch? If so that means the clutch itself is gone.

Mar 10, 2009 | 10:59 AM

lsrx101

Fleet Mechanic

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From: Lorain County, Ohio

Check for power at the Cycling Switch connector.
- If you don't have battery voltage with the engine running and the AC on, the issue is back toward the control head.
-If there is power there, the issue is between the switch and and the compressor.

With the engine running and the AC on, CAREFULLY tap the clutch face with a dowel, hammer handle or other similar tool. If the clutch engages, the clutch gap is too wide. This is a common problem on FS-10 compressors as the clutch wears. You can remove a shim behind the clutch plate to decrease the gap. It's not a critical measurement, .020" or less without the plate rubbing while disengaged.

May 26, 2009 | 11:36 AM

mdcyr

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V-10 A/C compressor doesn't engage

Thanks for the ideas. I was able to verify no voltage at compressor and a mechanic was able to apply voltage at the relay box and got the compressor to engage. So it looks like it is upstream from the relay, but I don't really know what to look for at the head end. Any more ideas?

Thanks in advance.

May 26, 2009 | 06:13 PM

azcactus

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From: Tucson, AZ

I have the same problem with my 2000 V-10 X. According to the wiring diagrams the A/C clutch is controlled by the PCM- I am continuing troubleshooting but so far everything points toward the PCM. Anyone more familiar know if this is true?

May 26, 2009 | 08:13 PM

projectSHO89

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From: St Louis

Make certain the PCM has the correct input(s) before jumping to the conclusion that the output is incorrect.

May 26, 2009 | 08:31 PM

azcactus

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From: Tucson, AZ

I am not done checking yet, so far everything under the hood is checking out- relays ok, fuses ok, high pressure cut-off good, cycling switch good, charge is good, clutch works when jumpered. I get clutch activation for about 10 sec when ac turned on- then nothing.. . .a couple of weeks ago it was about 5 minutes of cooling before it stopped working, now 10 seconds (just enough time to get around to the front and climb-up to peer at clutch to see if working. Now I am working my way inside. Checking the console switch and wiring to the blend door motor (it's in the diagram).