Air conditioning compressor on-off
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Air conditioning compressor on-off
89 F150 with 4.9. For some time, notice engine switching - click noise then rpm drop then switch back. Back and forth at 10 -30 sec intervals while at idle. I finally discovered it is the air conditioning clutch engaging and disengaging. This accounts for noise and rpm drop. The A/C does not even work and is in off position at switch.
Any ideas why or where the signal is coming from?
More important, can I just pull the wire connector into the compressor to keep this from happening?
Any ideas why or where the signal is coming from?
More important, can I just pull the wire connector into the compressor to keep this from happening?
Post Fiend
Joined: Oct 2003
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From: New Jersey
You can pull the wire to the clutch, and it will stop.
What is happening is your AC has enough gas in it to allow it to cycle, but not enough gas in it to do anything useful. So it needs to be recharged. Which means it probably leaks at the back of the compressor housing, or at one of the joints along the way to the condenser inside your heater core assembly. Just a few o-rings and some special tools to pull the joints apart.
If you choose to fix this, replace the evaporator. It's a cheap part and it being new and moisture free makes the world of difference in AC performance.
What is happening is your AC has enough gas in it to allow it to cycle, but not enough gas in it to do anything useful. So it needs to be recharged. Which means it probably leaks at the back of the compressor housing, or at one of the joints along the way to the condenser inside your heater core assembly. Just a few o-rings and some special tools to pull the joints apart.
If you choose to fix this, replace the evaporator. It's a cheap part and it being new and moisture free makes the world of difference in AC performance.
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Thanks to all. I will pull the connector into the compresser. I am still flummoxed as to why the clutch engages as the switch is off. The gas leaked out the day I drove it home over three years ago and thereforte not even had the A/C on since.
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Fleet Mechanic
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From: Michigan
If you use the defrost or mix options on your climate control, this tells the compressor to cycle also.
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I HAVE SAME PROBLEM (same year 1989 F150 302) --- Let me explain clearly.
Climate control on (A/C) and the A/C works normal, cools like ice.
But when the climate control slider is OFF, then the A/C cycles at 10-20 sec intervals. I have read that the A/C system is "designed to cycle to extend compressor life" (i.e. lubricating the seals). But every 10-20 seconds is ridiculous. I have resigned to unplugging the electrical connector to the compressor unless I want A/C when it's hot.
Does anyone know what electrical system controls the cycling of the compressor intended to extend compressor life?
Climate control on (A/C) and the A/C works normal, cools like ice.
But when the climate control slider is OFF, then the A/C cycles at 10-20 sec intervals. I have read that the A/C system is "designed to cycle to extend compressor life" (i.e. lubricating the seals). But every 10-20 seconds is ridiculous. I have resigned to unplugging the electrical connector to the compressor unless I want A/C when it's hot.
Does anyone know what electrical system controls the cycling of the compressor intended to extend compressor life?
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