Fan Resistor
 

Can someone confirm please? A delicate, low volume whirling fan sound from behind the dash below the radio. Sometimes it's there and sometimes not, continues after the car is off and locked. Parking gear transmission light glows on low, security light blinks and works fine. Car starts right up even after sitting for a few days. This X5 2001,3.0 did sit for 5 months with a drip charger while I was away.
I did have the Fan Resistor replaced two years ago. What is the best brand to replace this with?
J

The fan noise coming from behind the IHKA control panel is not the same thing as the HVAC blower fan that the FSR/FSU controls.

The little fan inside the IHKA draws air into the IHKA across a thermistor which regulates/maintains the TEMP that is set on the control panel. This little fan operates when the vehicle is in WAKE mode...and shuts down when the vehicle goes into SLEEP mode (16 minutes after shut down of engine and there's no "calls" on the door modules or remote buttons).

The e38/e39/e53 have similarly designed IHKAs....the e38 is slightly different with it's passenger side redundant buttons...but again, the interior design is basically the same, as well as how you open the IHKA control unit.

If you are sitting inside the car waiting for the little fan inside the IHKA to stop...you've gotta remain in the car for the whole 16 minutes without touching/lifting/activating anything on the P-bus that will keep the car AWAKE:


Below are pics of the fan in question...images are from farnarkler's DIY on e38.org:


Here's another image which also shows how dust can build up on the fan...this one is by Mario (another e38.org DIY on this issue)...and a link to his DIY (which shows how to set-up the plastic tabs to open the IHKA control unit:

Also, the light on the transmission selector does not indicate sleep or wake mode. It has no bearing on what mode the vehicle is in.

If you want to troubleshoot further, you need to determine what the current draw is when the vehicle is awake and then asleep.

This is absolutely amazing post. Thank you. I imagine one day soon I will tackle cleaning the fan if it's necessary to avoid further problems. I am wondering where the modules are and what they cost to replace. Again, thanks for clarifying the noise before I bought another Fan R. BTW, is the "P"arking light supposed to be illuminated after sleep mode?
Thanks again.

The indicator on the gear selector goes out on some vehicles, and stays on with others. It has no bearing on whether the vehicle is in sleep mode or not. Mine stayed on.