My R4 compressor never cycles, either

[Sawlty]

Can anyone here explain to me how you adjust the low pressure cycling switch that’s accumulator mounted?

I have a 94 Suburban k2500.

This is the first time I’ve heard of adjusting the switch.

Thank you,
Sawlty

[tbirdtbird]

You are posting on a 2-year old thread, better to start your own

[JohnHere]

Can anyone here explain to me how you adjust the low pressure cycling switch that’s accumulator mounted? I have a 94 Suburban k2500. This is the first time I’ve heard of adjusting the switch.

I'm not familiar with your particular cycling switch. But IIRC, some of them have an adjustment screw between the electrical terminals, while others have an adjustment nut (for lack of a better term) inside the end that attaches to the accumulator. And some aren't adjustable at all.

For the adjustable variety, there's no calibration per se. It's a matter of experimenting with the adjustment until you arrive at the sweet spot.

Maybe the existing switch has failed. Have you tried replacing it with a new one?

[GM Tech]

Adjustable cycling switches haven't been used for over 30 years---Everything used on GM vehicles are non-adjustable--(no screw between terminals). Cycling switches are there to avert freeze-up and low refrigerant charge (pressure) ruining your compressor. If it is not cycling- it's most likely the suction pressure is not low enough, that there is still demand for cooling the evaporator. Typical suction pressure low pressure cycling switches cycle off at 22-24 psi and on at 30-34 psi or so...So does your suction pressure agree with this?

[JohnHere]

Curiously, an acquaintance owned a 1993 Suburban that had an adjustable clutch cycling switch.