1 Fan Running Continuously Tue Oct 26, 2010 3:35 am
geo
New member
1990 4 valve K100RS with Motronic Box
The fan runs continuously from the moment the engine is started from cold. Have removed and verified the varying resistance of the temperature sensor in hot water then reinstalled. I then disconnected the leads to the temperature sensor which I believe provides an infinite resistance and still the fan runs. Next I removed and changed the fan relay for a new one and the fan continues to run. Looking at the Clymer schematics I see a connection to the I just betchya probably really demoralizingly expensive Motronic box and am really hoping this is not the source of difficulty. Has anyone run into this problem or can make test suggestions other than riding everything over a cliff?
I see a number of posts about installing a separate switch to turn the fan off and on manually but I would prefer to have it work as BMW intended.
Thanks
geo
The fan runs continuously from the moment the engine is started from cold. Have removed and verified the varying resistance of the temperature sensor in hot water then reinstalled. I then disconnected the leads to the temperature sensor which I believe provides an infinite resistance and still the fan runs. Next I removed and changed the fan relay for a new one and the fan continues to run. Looking at the Clymer schematics I see a connection to the I just betchya probably really demoralizingly expensive Motronic box and am really hoping this is not the source of difficulty. Has anyone run into this problem or can make test suggestions other than riding everything over a cliff?
I see a number of posts about installing a separate switch to turn the fan off and on manually but I would prefer to have it work as BMW intended.
Thanks
geo