URO Parts 17117561757 Auxiliary Cooling Fan Assembly - Replacement Radiator Fan for BMW 3 Series 5 Series X5 - Perfect for Overheating Prevention & Engine Cooling in Hot Weather

I had a problem where my fan was running all the time with or without the key on. No real good YouTube troubleshoot videos. There were some reports that it was the fan controller attached to the fan which is part of the 2-speed controller. Reports said that the controller was bad. I could not test to verify so I did not believe the reports. I tested the fan switch by removing the switch/sensor and obtain an ohm reading when cold. Then I heated water in a coffee cup in microwave to 200 degrees or so and placed sensor in water. Ohm reading changed. So, I assumed fan switch/sensor was good. I did not replace it. I removed the fan and looked closely and the fan controller and found corrosion on the terminals. So, I thought maybe there was a problem with the circuit board and moisture got into unit. I cleaned the terminals and placed fan back in service. My original problem was the fan always ran with key on or off. When I hooked up power to fan it came on as usual with engine off and cold which it is not supposed to do. Then I heard short circuiting and fan shut off. I thought there was going to be a fire. I removed power by disconnecting electrical plug to fan and removed fan. At this point the speed controller was burnt up so I had to buy a new fan. Once I got new fan I installed it and everything worked as it was supposed to! Fan stayed off when engine was cold with key on or off. Once engine reached temp fan turned on. Fan ran on high when AC was turned on! Fast delivery and correct fit and size! During all this testing I did check fuses and tried to locate a fan relay in fuse box but never could verify if there was a relay or not. Car is 2002 BMW 325i E46 with 240,000 miles! Time for a new fan! lol