2012 Plugin AC cuts off at 75 degrees

Unclear: You mean that above 75 (setpoint? outdoor temp?) the cooling fails (?) and the fans go to high speed, or off?

 

Welcome, Harold. You might want to check that there's enough freon. There's a sight glass in the low pressure line at the passenger side of the compartment. The quick and dirty check is to see if there are bubbles there when running the A/C full blast on a hot day. Bubbles mean low pressure. Beyond that, you'd need gauges that have not been used on a regular A/C since even a little regular A/C oil will destroy your compressor, and know how to read them.

 

Yikes. I hope you can find a shop that's experienced with hybrid A/Cs. Sounds like your dealer plans to replace everything. The compressor on my PiP ate itself last year. I got a used one from a hybrid specialist dealer for $100 and the shop he uses for A/C work put it in for $200. Total cost, $300 plus tax. Obviously, if they have to get into the evaporator or other stuff under the dash, it'll cost more, but still ...

 

I don't know the electrical details of the PIP A/C, but it sure sounds like a faulty relay of some sort. Maybe find and change any relays associated with A/C and see what happens.

 

Overcharged? It will shut down if the high pressure limit is exceeded, and that would explain the over-a-certain-temperature part.