1) viscous fan isn't engaging to cool. 2) thermostat isn't working. So with my engine coolant temp at over 100C and car revved to 3k I was able to stop the Viscous fan quite easily! Using an envelope poked into the fan blades it stopped pretty quickly. I could do it with my fingers! The BMW 330i AC or heating fan not working can be caused by a variety of issues, including a faulty blower motor, fuse, resistor, or control module. Additionally, a clogged cabin air filter or inadequate refrigerant levels can also affect the performance of the fan. Auxiliary Electric Fan not working? Check the wiring. The break was in the right side wheel well behind the splash guard. If the fuse is good, then you may need to replace the wiring, not the fan - even if you measure 12VDC at the connector. Apparently - corroded wires don't conduct current too well. I have a 2000 Honda civic ex. The ac/heat worked great until a couple days ago. I noticed the fan was not blowing any air through the vents. Then all of a sudden it started blowing full blast, while the recirc, ac, rear defrost button lights all came on and were flashingthen it all turned off. - 1996-2000 Honda Civic The most common symptom of a failed blower motor resistor is when the heater fan only runs at the highest speed setting (4 or 5) and doesn't work at low speeds. In some cars, a failed blower motor resistor can cause a heater fan to stop working completely. In most cases, a blower motor resistor fails due to corrosion or overheating. shanneba. The fan may not come on when you switch on the A/C. If the ambient air temp is cool and the A/C pressure is low the fan may not be needed. I would check for any codes in the IHKA system with something like the BMW scanner software 1.4. The fan should turn on for a second when you first turn on the ignition, it should spin down and stop. 6458 posts · Joined 2012. #11 · Jun 26, 2016. Auc pressure sensor should be located at the auc dryer canister. It determines the pressure and thus controls the fan speed. Fan fault could be linked to the pressure sensor. G30 520d xdrive msport 2017-current. E60 520d 2007 lci saloon-current. E46 320d 2001 saloon-current. this video will show you how to fix your air con for less then £5 pound on any bmw and what to check please check out my good buddy nathans channel for all b S9NPLT.