TE250 2011 THERMO FAN QUESTION

Hey guys,
I know this topic has come up before but i still can't get an answer.
My thermo fan has never come on, I tested it on the weekend by hooking up a 12v battery and it worked fine. I have heard it could be a faulty thermo switch, My question is where is the thermo switch?

THANKS!

I believe on the blackheads the ECU uses the CTS (coolant temp. sensor) on the back of the cylinder (next to the cam chain tensioner) to determine when the fan comes on. Later red heads have a separate sensor (to control the fan only) in the radiator hose.

btw, "your" sensor is famous for going out and causing the bike to run rough. $15-20 IIRC.

sometimes called a WTS (water temperature sensor) in different manuals. The Italians did a terrible job of translating stuff into English in most of their manuals.

edit: I just found a reference to it in my manual denoting it as a "coolant temperature thermostat". sheesh. that's about the 5th or 6th name I've seen for it.

quick test you can do to check if the problem is the temp sensor, warm the engine up at least 15 min, or run it around enough to get the engine to temperature, then shut it off, then disconnect the temp sensor. your fan should run.

At least that is the way I have discovered my temp sensor is bad. I have the exact same bike.

I had a new sensor changed years ago under warranty, even since then the fan has never come on, I will give your method a try though.
What if it still doesn't come on, whats next?

weird test. I'm wondering why you need to get the engine warm first. ...oh, wait- got it: to get it to the temp where the fan SHOULD be on (but isn't).

this test is slightly backwards; if unplugging the sensor turns the fan on (when the key is on)- do that first and last. If the fan comes on, then continue by starting the motor with the sensor plugged in, up to operating temps. later if the fan never comes on, shut the bike off and unplug the thermo sensor again, [edit] to cool the bike off.

if the fan doesn't come on with the unplugged sensor in the first place- you've got a fan or a fuse or some other problem. No need to stress the cooling system otherwise.

Alberto- where didja get this test from? pretty handy if it's legit.

LOL! I will check the fuse tonight.

haha trial and error, but your suggestion seems easier, I've never tried it.

What a great tip! I have a TE310 that NEVER runs it's fan, and I always wondered if the fan was broken or something. I run my bike pretty hard, but it never overheats. I'd changed out the sensor years ago as a PM item 'cause I'd heard the original was prone to fail.

So for me, this was a simple way for me to test my fan. Thanks Alberto!

SO did your fan come on?

I have a 2010 TE250 and the fan never came on even when it was new and I had it buried in a mud hole during 2010 Sandy Lane enduro.
I took the fan off. it never boiled either. I have about 150 hrs on it.

OTOH, my '12 TXC310's fan comes on all the time.

More heat out of the 310? The 12pt injector running hotter, who knows.

Yep.