This switch is used only on 2008 and earlier models with accumulators. Later models with receiver/driers don't use a pressure cycling switch. The pressure cycling switch is located on top of the accumulator and detects low refrigerant line pressure at 22 to 28 psi. It switches the A/C system off and then back on again at 40 to 47 psi. If the pressure increases over 550 psi, the pressure cut-off switch shuts the system off. To replace the pressure cycling switch, unplug the electrical connector, unscrew the switch from the accumulator, lubricate the switch o-ring with clean refrigerant oil, screw the new switch onto the accumulator threads until hand tight, and then tighten it securely. Finally, reconnect the electrical connector.