A/C compressor is not turning off

1998 MERCURY VILLAGER
225,000 MILES • 0.6L • 6 CYL • 2WD
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BOP7176
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  • 4 POSTS
My A/C compressor does not shut off when the HVAC button is off.
Apr 11, 2017 at 10:07 AM
Repair Safety Notice: This information is for general instructional purposes only. Vehicle repair can be dangerous. Verify all information, follow manufacturer service procedures, use proper tools and safety equipment, and consult a qualified repair shop when needed.
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STEVE W.
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 15,146 POSTS
Do you have defrost selected? If so the A/C will run to dry out the incoming air to help prevent the windshield from fogging.
I you do not have defrost on, it is possible the clutch has an issue and is causing the compressor to keep turning. With the engine off, you can move the tension-er and loosen the belt. Now try turning the drive pulley by hand to see if the clutch is damaged.
Apr 11, 2017 at 2:47 PM
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BOP7176
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  • 4 POSTS
Did all that and it still stays on.
Apr 12, 2017 at 10:13 AM
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STEVE W.
  • AUTOMOTIVE REPAIR CONTRIBUTOR
  • 15,146 POSTS
Remove the A/C relay from the under hood relay box and see if it shuts off. If it does then swap the relay with another one in the box and see if the clutch re-engages. If it stays off the relay you removed is bad.
If it turns back on you will need to use a scan tool to test the PCM and determine if it is commanding the compressor on and why. It may be a faulty PCM or control head. For both you need a good scan tool to test the system.
Apr 12, 2017 at 5:30 PM