Very Strange issue 2005 tahoe

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FLORIDA1

FLORIDA1

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Oh ok, I see he has extremely corroded connectors on the ECM harness. That’s going to cause all sorts of issues. Short circuits of all kinds there. @FLORIDA1 why do you have 2 threads going on?
Sorry, really my first time posting on the forum.
Really didn't know where to post to start with.
 

RET423

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The A/C fans kick on when the high pressure side of the A/C reaches its maximum designed pressure, if the pressure does not drop quickly enough the system is supposed to cut power to the A/C compressor to save it from locking up and destroying it.

It sounds like your high pressure safety switch is not disengaging the A/C clutch when it should, so your fan comes on but the compressor keeps pumping up the pressure until it starts locking up (and stalling the engine)

The pressure switch is likely bad but it also sounds like you have too much freon or significant moisture in the system if the high pressure lockup is occurring that quickly after the fan kicks on.
 

Rocket Man

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The A/C fans kick on when the high pressure side of the A/C reaches its maximum designed pressure, if the pressure does not drop quickly enough the system is supposed to cut power to the A/C compressor to save it from locking up and destroying it.

It sounds like your high pressure safety switch is not disengaging the A/C clutch when it should, so your fan comes on but the compressor keeps pumping up the pressure until it starts locking up (and stalling the engine)

The pressure switch is likely bad but it also sounds like you have too much freon or significant moisture in the system if the high pressure lockup is occurring that quickly after the fan kicks on.
See post #2 of the OP’s other thread for the problem. It was extreme corrosion on the ECM harness connector, likely shorting the fan voltage to a couple injectors.

 
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