Some background - my 2017 crf250L gets plenty hot and the fan is not turning on. I have 6,000 mi on it and I'm very familiar with when it usually turns on. However on a near 100 deg. day on a long ride, I noticed it was not turning on. I called for help to get it home without further heating. More testing at home and fan still will not turn on.
I disconnected the fan and gave it power - fan comes on.
I'm thinking that the ECT sensor (basically a temp. sensor switch) is the next most likely failure, so I disconnect the 3 pin connector and plan to cross two terminals and see if the fan comes on. I'm thinking that this would tell me if the ECT was bad. If it came on while hot wired, and if it did not come on to keep searching.
Here is where I'm lost - With the key on of course (engine not on), No fan while connected (normal, because not hot). When I disconnect the wiring plug to the ECT the fan comes on. The thought the ECT was basically a temp switch that should interupt current when not to temp right? Why does the fan come on when disconnected?? What does that tell you? I'm confused.