Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
A/C Cycling Switch
The A/C cycling switch is mounted on a Shrader-type fitting located on top of accumulator-drier. A valve depressor, located inside threaded end of A/C cycling switch, presses in on Shrader valve stem. This allows pressure inside accumulator-drier to control A/C cycling switch. When contacts close, voltage is applied to A/C clutch field coil to operate compressor. When contacts open, A/C clutch is de-energized and compressor stops. A/C cycling switch will control evaporator core pressure to a point where surface temperature of evaporator core is maintained slightly above freezing. This prevents icing of evaporator core and air flow blockage.
The A/C cycling switch closes when pressure on low side of system reaches approximately 40-47 psi (2.8-3.3 kg/cm2 ). A/C cycling switch opens when pressure drops to approximately 23.5-25.5 psi (1.7-1.8 kg/cm2 ), disengaging A/C clutch. In ambient temperatures below 30°F (-1°C), A/C cycling switch will not allow compressor operation because of low system pressures.
NO RELATED
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
Affiliate disclosure: We may earn a commission at no extra cost to you.
When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.