88-94 A/C light blinks

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Lifted92

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I have a 1992 GMC K1500 and the A/C light blinks in the HVAC controls. The compressor is about 5-7 years old, new lines, new orings, new hi pressure sensor and fully charged. If the battery is disconnected and reconnected the compressor clutch will kick on and off repeatedly until the light starts to blink. I've tried different controls from a scrapyard, but to no avail, any ideas?
 

someotherguy

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Need to check your charge and operating pressures, preferably checked by an experienced A/C tech. If the clutch is cycling very often then the charge is incorrect. The control unit is disabling the A/C to prevent compressor damage.

If it was cycling at a normal rate and the same blinking A/C icon and disabled compressor happened, there's a service bulletin out on false error condition that requires just cutting/removing one wire from the harness to the controls. However, it sounds 100% like in your situation it is behaving correctly.

Richard
 

Lifted92

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I know for sure it's not low on freon, but it seems no matter how little or how much pressure I have it still disables it. It's also been to a shop a couple times with no change, I guess I'll try to find a good one, thanks fellas!
 

someotherguy

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If it's cycling a bunch as you implied, then it's likely not correct. That's the symptom the A/C control is looking for in order to signal an error and disable the compressor. I don't know the specific # of cycles within a particular time period, but that's the scenario.

Richard
 

VenomousSVT

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if you are sure its not the refrigerant then its your ac pressure switch. Mine did this years ago, i picked up the $17 switch from advance and it took 1 minute to replace. problem solved.
 

VenomousSVT

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I know for sure it's not low on freon, but it seems no matter how little or how much pressure I have it still disables it. It's also been to a shop a couple times with no change, I guess I'll try to find a good one, thanks fellas!
meant to tag you so... look up
 
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