My 86 Chevy Cavalier has a high and low pressure switch in the compressor. There is no switch in the accumulator - I was looking for it for ages!! In the end my problem was low refrigerant AND a faulty compressor control relay. You need to do some slow logical fault finding - that's why I am starting to like a/c systems - they are rather like fault finding electronic circuits. Having a manual is almost essential. My car has a variety of switches and relays which all serve to allow or prevent the electric clutch on the compressor from being activated or this is just a cavalier. I am sure that your vehicle is more complicated still.

I wonder if your shop has diagnosed the problem correctly or are they just guessing

regards Mark

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