* Thermostatically Controlled (Automatic): This is the most common method. A temperature sensor in the engine coolant detects when the coolant temperature rises above a certain point (usually around 200-220°F). This sensor signals a relay, which in turn activates the electric cooling fan motor. The fan will run until the coolant temperature drops to a safe level. Some systems may have multiple speeds (high and low) depending on temperature.
* A/C Control: The cooling fan may also be activated when the air conditioning system is running. The A/C compressor generates heat, and the fan helps dissipate this heat to maintain optimal A/C performance. This is often a separate circuit, meaning it can run independently of the engine temperature control.
In short: The system monitors engine temperature. If it gets too hot, the fan activates to help cool the engine. If the A/C is on, the fan will assist in cooling the A/C condenser as well. This typically involves a combination of sensors, relays, and wiring harness. The fan itself might be a single-speed or multi-speed unit.
Important Note: A malfunctioning cooling fan (either failing to turn on when needed, or running constantly) can lead to engine overheating and serious damage. If you suspect a problem with your Pontiac Montana's cooling fan, have it inspected by a mechanic as soon as possible.
