I feel your pain, I am a retired mechanic and have dealt with issue like yours, had a brand new truck that the a/c would quit working intermittently, the dealer replaced everything to do with that system and would say it ram for 8 hrs on the lot and is fixed and as soon as truck left it would quit again, I finally hooked up a computer to be able to monitor all a/c signals and found on hard bumps the a/c would go into emergency shutdown mode but would work again on cycling the key, wiggled every harness till I duplicated error, found the main harness going into cab had a wire wrapped around the bolt holding the harness into the block, repaired that wire and fixed the issue, but it took over a year to get to that point.
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