oil cooling fan and temperature light

[mga]

is there any way to test these? i know the fan works if i jump it, and i believe i heard it turn on once when driving, but the light has never come on. the bulb is good ( i checked it on the bench)

is there a way to test the sending unit for the oil temp?

[Gwbarm]

You can heat the sensor with a heat gun and see if the fan and light come on, to do this remove the sensor, there are ohm ratings that you can check with a meter, your manual should tell you the correct specs.

[Mech]

You really need to get the manual and follow it's diagnosis process.

There is a temp sensor, a temp control unit, and a relay and circuit breaker for the fan. If neither the fan nor the light come on it could be the unit or the sensor, but the light is meant to come on when you use the electric start as a check, so follow the diagnosis process to make sure you find the problem

[mga]

i tried looking at many manuals for this issue, they all seem different. But, i saw on a diagram when i followed the wires supposedly for my year and make, there is something called a "oil temperature indicator light checker" near or in the main switch on the handle bar.

I jumped the oil temp switch earlier and the fans turned on, but the light never did. supposedly it's supposed to light up when the fan goes on.

Is that oil temperature light checker a real thing? i can't seem to find any info on that

[Gwbarm]

I would think the light would only turn on when its hot, when it heats up to a certain point you get a clear path from the sensor for 12 volt to go to the light bulb to tell you its running hot.

[Mech]

If this is the 2000 BB400 then this is what you need I think.. As always, if the wire colours don't seem right let us know.. Yamaha love to change their wiring.

One thing to note is that the wire going to the temp light changes from R/w to Br at a splice in the main power wire from the fuses. Those splices(shown as dots on the wires) are sometimes just crimped joins and can get dirty when they are old.

output.pdf

[mga]

On 8/28/2023 at 4:50 PM, Mech said:

If this is the 2000 BB400 then this is what you need I think.. As always, if the wire colours don't seem right let us know.. Yamaha love to change their wiring.

One thing to note is that the wire going to the temp light changes from R/w to Br at a splice in the main power wire from the fuses. Those splices(shown as dots on the wires) are sometimes just crimped joins and can get dirty when they are old.

output.pdf 144.14 kB · 2 downloads

fixed! a couple of bad connections i found following your diagrams.  light works now

thanks a million!!!!

[Mech]

Good one.

[Gwbarm]

Great you found those, they are sometimes hard to track down.