I was threadjacking earlier so thought I'd best start my own thread here. Low fuel warning light doesn't come on. Is there a way to trip the light manually by jumping wires, to confirm the circuit other than the sensor itself is ok?

So a further investigation the other day found that I had a burnt out bulb. I changed the bulb but had a full tank of gas, so it didn't turn on yet. However, today I was moving some bikes around (now have 3 BMW's...) and this bike was outside in the very cold (-5*C plus brutal wind chill) after having been moved from my 'not as cold' garage. I noted that the fuel light was now on... with lots of gas in the tank. Do you think the sensor was tripped by the cold fuel? I know that sensor on the RS is supposed to trip when it is partially exposed, causing a temp difference inside it, etc etc etc. Maybe Bert knows more since he's studied the electrical parts in detail?

Club_C

Sorry, I missed your post and question.
Your K100 is an early one and has the electronic fuel sensor and the sender works on the difference of temperature between the air and the fuel
Here is what I think happened:
In normal condition, the air in the tank is warmer than the fuel.
You may have left the bike outside just long enough to have the air cooling off a lot faster than the fuel and this could have the sender 'confused'.
Now that you have the bike back in the garage do you still have a problem?

Bert