Hiya I have an intermittent fan error when bike hits 103 desgrees and the fan kicks in. If i hotwire the fan it works fine. In the hot weather sometime the fan gets to 103degress and kicks in fine. Sometimes it gets to 103 degrees , kicks in, then cuts out with a fan error appearing on the dash. All wiring looks fine. When i turn engine on/off it resets the error and next time it may/may not work. Ofcourse this always happens on hot days - when you want the fan - by definition, or the fan wouldn't be coming on in the first place!! i did leave the bike idling for ages on a cool day and the fan kicked in and ran - but no proof of anything as sometime it'll do that on a hot day too. Thoughts are: 1) duff fan - and some sensor detecting its pulling too much current? 2) just some duff sensor somewhere? 3) the magnetic pull from the moon on thursday afternoons 4) if the bike is running hot near a magic pixie they cast a spell on the fan Anyone had the problem and fixed it - or sound suggestions on how to debug , ideally without having to get another fan to test.
When the coolant temperature reaches approximately 103 degrees the fan is commanded "ON." If the command is issued and the fan doesn't respond, a "FAN" error and an EOBD indication will appear on the dash. If the coolant temperature is below 103 degrees when the bike is again keyed to the "ON" position, the "FAN" error and EOBD indication on the dash will clear. The coolant sensor sends temperature information to the ECU. The ECU communicates/shares this information with the BBS across the CAN bus. The fan is wired directly to the BBS. As the connection to the BBS has proven to be problematic on some bikes (in some operating environments) due to the formation of condensation at the connector, this may be an area to explore. Open, inspect, and clean the connector. The BBS is located directly beneath the rider's seat, and like the ECU, dash pad, ignition switch module, etc., is one of many nodes attached to the CAN bus (network). CAN technology is a priority based message protocol that allows all information to be shared between nodes attached to the network.
I think that's the single best explanation on any topic I've every had !! thank you very much for taking the time to write it!!
