Cooling fan still running

I can't find anything using search so here we go...

I got the bike out of the shed this morning to do some maintenance.
As soon as I turned the key on the cooling fan started. Start engine and let it run for a couple of minutes, fan still running. Stop the engine with the kill switch, fan still running, switch off the ignition key and fan stops. Ignition on again, and the fan starts.
The last time I was out on the bike was last week, mild winter temperatures, when I got home the fan was running but this is normal after a brisk run because the last mile is uphill.

What could be causing the fan to run all the time?

There could be some corrosion in the connector to the fan (hidden alongside the left hand side if the radiator, almost).

Then there's the fan relay. You may remember that I found severe corrosion in the relay, although in my case, it was stopping the fan coming on!

Lastly, it's the water temp sensor. This tricky but not too off-putting.

Just some ideas,

Good thoughts, I'm suspecting the fan relay or water temperature sensor as it failed on.
But further investigation is pending me completing the work on the forks, about which I might start a separate thread providing I don't lose me rag and torch the bloody lot 🤬

I know that feeling. If you've got the front cover off while doing your forks, the fan relay is under there.

What's the problem with the forks?

Topic has been split. See “Fork tube jammed”.

Cheers, my OCD is calming down

Thanks for splitting the topic Tim.

Never mind the OCD, I want hear how this turns out. The good thing about having two simultaneous problems occurring is that you can be fettling with one, while you wait for the parts to arrive for the other one. It means that you're only 'off the road' for one period instead of two.

BTW, have you actually got the whole front cover off?

The whole front cover is off - repairing the cracks and tabs is the third job, but let's not go there or this will be schizm into a third thread! 🤪

Having Scootie off the road isn't a problem. The weather is utterly sh*t up here at the moment, and should it improve I have other toys in the cupboard

And after a happy fork rebuild its onto the bad news.
The fan wasn't running so I hoped it had sorted itself out. Reassembled the bike for a forking test run, ignition on and the fan is running.
Short test run done, the fan is still running so there is a problem.
Back into the shed and off with her knickers again!
First port of call the relay, and it checks out fine.
Relay reinstalled, battery reconnected, ignition on, press the starter button and all goes dead.
Bugger.
Checked the main and starter fuses, they are fine.
Next stop the relay, but for today it's been filed un "sod this for a lark" and I'll return to it another day.
Watch out for the next exciting installment.

Well, here's a long shot. Could the coolant sensor connecting plug be corroded?

It would explain the fan coming on and could be causing short circuits elsewhere.

That's something I need to check out next, something is switching the relay on and the coolant sensor could be the culprit.
But the fact everything has gone dead makes me fear a short somewhere, which might explain the sudden lack of electrics.
So that's fuses again, main fuse and coolant sensor in that order, then a look to see if any part of the wiring loom looks exposed to cause a short.
God I hate electrics, can we go back to kick-starts and carbide lamps please and dispose of all this electricity?
But none of that's happening today because after yesterday's bloody freezing and snow we've now got bloody freezing, gales and rain - none of which inspires me to go to a unheated shed.

Today I braved the shed again.
Regarding the all dead bit that was pure idiocy on my part, ie a poor battery connection.
Battery charged, terminals cleaned, ignition on and the engine starts.
Deep joy.
The fan is still running though and as the relay is fine the next thing to check is the thermosensor. Where does that live?
The FSM says first remove luggage box!
The mission continues ...

From memory, the thermosensor is under the plastic cover under the seat.

A little later to the discussion but… the coolant temp sensor is located under the seat undercover and sits above and to the left of the engine. It is has a triangular shaped plug with, um, three wires.

Today I've taken the Missus to the train station for a girlie day in York (and collected a slightly drunken version later), took the Tenere in for its  MOT (a UK thing) and spent 3 hours removing plastic in search of the elusive sensor.
There is still a few bits of fairing left on the bike. They will come off tomorrow so if its not the sensor at least she (the bike, not the wife) is standing naked in the garage for an electrical genius (not me) to do some electrical fault finding.
For now I'm consoling myself with Theakstons Old Peculiar.

Ahh, Theakstons OP. Probably the best beer in the world, but at 5.6% it can be dangerous. Enjoy, oh, and keep us posted.

steve_h80 wrote:

For now I'm consoling myself with Theakstons Old Peculiar.

As well as this current endless and rather monotonous stream of topics on mechanical problems.  I'm now consoling myself that you can't correctly spell the name of that fine and famous Theakston beer that's brewed a pleasant 48 miles ride up the road from York in Masham, North Yorkshire.

It's called Old Peculier, not Old Peculiar.  In Masham as part of the brewery there's the Black Bull in Paradise Visitor Centr,  and a decent shop if you want to buy beer and Theakston merchandise.

It has a rival though. in the nearby Black Sheep Brewery, set up by Paul Theakston the so called 'black sheep' of the Theakston brewing family.

I usually have an annual ride there, I'm not so much interested in the beer there as it's widely available locally, and of course I don't drink and ride. What I like to do is have a poke around the shop and maybe order something from their Kitchen. It's very good and they do quite a few dishes using Black Sheep Beers.

In the summer months Masham seems to be a popular place for both cyclists and motorcyclists, as there's a large town square to park up and sometimes a market and food vans.  Masham sausages are a specialty sausage also worth trying too.

Thankfully Meldrew I'm beyond caring. Or I was after the second one

Just to close this great off.
After much faffing about the fan is now doing what it should do. I had the bruv-in-law (who is an engineer that understands electrickery) have a look af the naked bike and the wiring.
Nothing amis could be found so we concluded, it might be great temperature sensor failing (but the usually either work or they don't), it might be the ECU getting confused (again unlikely), a short somewhere in the wiring (possible but without unwrapping the loom that's not easy to find), or witchcraft. Presently witchcraft is deemed the most like likely culprit.
I then spent a pleasant Friday in the garage playing Eric Church too loud and put everything back together.
The bike now seems fine so I'm just going to wait and see, if it happens again I can pull the fuse as a get me home.

I hate unsolved mysteries. You could always rig up a switch if it continues to misbehave.

And it back. Sodding thing. 🤬🤬🤬🤬🤬🤬🤬🤬
So the fuse has been pulled and a manual switch will be installed before the weather warms up, I've got plenty of time before that happens over here.
As far as I can figure something is sending a false signal to the fan relay. I think I will pull the relay to open that circuit, then wire a fan switch from the relay switched side.
On a bike this old and limited value creative bodges are the way forward

You could try replacing the relay or swap it over with the headlight full-beam relay next to it, just to see. I think RS components do them at a fair price. You may recall my episode with the fan NOT coming on and I found the relay corroded beyond recognition. It might look OK on the outside but could be corroded inside.

The culprit has been found, that little blue/black wire at the bottom.

Hurrah!
Excuse for a party!

I can't tell what a relief that is! Party on!