radiator fan working intermittently

Hi, this is Bo, an auto expert on RepairPal's Car Genius team! If the radiator fan on that 2004 BMW X3 is working intermittently, there could be a few culprits. Since the previous owner already replaced the radiator, temp sensor, and expansion tank, the issue might lie with the fan control module, a relay, or even the fan itself. Electrical connections can sometimes be the gremlins in these situations, so checking for any loose or corroded connections is a good start. The fan control module, which regulates when the fan turns on and off, might also be on its way out, causing intermittent behavior. If the fan motor is worn out, it could struggle to engage consistently, especially under higher loads or in warmer temperatures. I always suggest getting a pre-purchase done to make sure there aren't any other issues occurring. Can't hurt! If you need any further advice or if you'd like any help finding a trusted RepairPal shop in your area, please feel free to call us at 877-913-1554!