Situation: My overtemp warning light comes on even when riding at speed.
Maybe overheating or is this a temperature warning sensor electrical whack light issue; I'm not sure.
I can't figure out if it uses the same sensor to sense temperature and provide a warning light, or is this a separate issue.
Background: the light has been coming on lately when driving even at high speed. The fan works, and the temperature gauge never goes anywhere near the red zone, but the temperature warning light comes on intermittently when the cooling fan is running. The fan will run without the light coming on at times, other times the light comes on at the same time. I'm trying to figure this out. I'm pretty sure this is not how it's supposed to work, but at least now I have a light that tells me my fan is running :)
So I did a coolant flush / refresh yesterday which I posted in "What did I do to my Brick today?" but am starting this as a new thread in order not to be highjacking that thread.
Draining the fluid:
Refilling with 50% concentrated OAT Prestone long life / heavy duty and 50% deionized water:
It took about a gallon altogether. This is more than the book says. Maybe I have the three core radiator as Jo suggested on the other thread but I don't know how to tell.
After it was all nicely done, the bike, when warmed up, still gives me the overtemp warning light in tandem with the fan turning on. The temperature gauge, however, never goes much above the middle. Certainly never into the red.
So I thought, maybe the thermostat is stuck. The hoses felt hot both to and from the radiator so maybe was wrong in retrospect but the radiator itself did not feel hot to touch.
So any fellow RT owner knows, the somewhat laborous removal of various fairing pieces comes next. I'll spare you the photos.
Removal of the thermostat is pretty straightforward.
Measured when cold:
2.5 cm
Measured at 170 degrees:
3.5 cm
So cleaned and put everything back together.
Problem persists.
Assessment: Either my bike is overheating (although the gauge doesn't think so and no overflow that I've seen yet) or the light circuit is somehow connected to the fan on circuit intermittently.
So now I don't know what to trust. Fan runs. Temperature gauge stays in the middle of the range. Temperature warning light comes on at the same time as the fan, sometimes dim, sometimes bright, seems to flicker if I put on additional electrical load such as hand heaters or high beam or even brakes (activating brake light).
Could be an electrical issues, ground maybe, but my god what a mess of wires under the fuel tank. The likelihood of me screwing something up is at least as high as me figuring this out.
Has anyone ever had a similar issue, and is there a straightforward fix?
I am moderately reassured by Frankenduck:
Probably a design or cost issue. It's really not all THAT important as, just like in a car, the radiator cap will blow before engine damage is done.
The other way would be to pull the back of the instrument cluster off and test the bulb.
Since it never goes on the chances are very high that it's as good as a brand new bulb.
Then I see this post from Martin . . makes me think that whatever tells the bulb to come on is cutting in early but that might be just wishful thinking.
Liverpool Thermostat starts to open 186 F, Fan cuts in 217F, Warning light , activates 232F.
Regards Martin.
Recommendations?
My next plan with this is to run the bike see when the light comes on, and tape a temperature probe to the hottest part of the cooling system and see what the coolant temperature is at that point. Does that make sense? I am reluctant to get into the spaghetti of wires under the tank if I can at all avoid it.