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#1
06-09-2026, 01:02 PM
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a/c compressor cycling too fast
i have a 77 g/prix, when i got it the a/c comp. would cycle constanly. so i figured it was low on freon, converted to r134a does the same thing. if i bypass the temp switch [ the one with the probe]compressor runs constantly so i figured switch was bad ,put a new switch on does the same thing, what else controls a/c clutch. it does blow cold when switch is bypassed
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#2
06-09-2026, 02:28 PM
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Low pressure switch is different for 134a, some of them are adjustable. Low side switch should open around 22-23 psi. You need to put gauges on the system and see what's going on. Post your idle pressures, high and low with the switch jumped out.
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#3
06-09-2026, 06:38 PM
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Found the issue, someone put temp switch probe on the a/c line that gets real cold quickly. I moved to the evap core seems ok now
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#4
06-10-2026, 10:08 PM
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Glad you found it. 1977 Firebirds used an evaporator temp switch to control clutch cycling, so I didn't know if the GP did too. By 1979 for sure I've seen pressure cycling setups only.
Pressure cycling switch on the accumulator became the standard for decades after that. I love the simple orifice tube systems.
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