The special button (ice symbol) on the climate control system control unit switches on the air cooling and dehumidification circuit, activating the air conditioning compressor.The above button enables the operation of the air cooling circuit, but the actual compressor activation is also dependent upon the activation of:- the fan linear sensor, located on the coolant circuit that locks air conditioner activation if coolant pressure is too low or high;- the engine control unit that excludes compressor operation in accordance with engine management mode; e.g. in the case of high engine temperatures or high engine load (sudden acceleration);Automatic climate control: If the compressor is enabled and the engine started, the control unit that controls the manual ventilation does not go below a minimum value.Manual climate control: when the compressor is activated, the fan is also driven at first speed via a relay located inside the unit.For more details See descriptions 5040 AIR CONDITIONING CASING AND COMPONENTS The supply circuit for the compressor is controlled by a specific relay and protected by a special fuse, both located in the engine compartment junction unit.The fan receives a power supply from a line protected by a special fuse and operated by a specific relay in the engine compartment junction unit.The controls receive a power supply from an ignition-controlled line protected by a fuse in the junction unit under the dashboard.