COOLING FAN NOT COMING ON?

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cb4265
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COOLING FAN NOT COMING ON?

#1 Post by cb4265 » Mon Mar 26, 2007 4:23 am

HI GUYS,
CAN ANYONE GUIDE ME IN THE RIGHT DIRECTION?

THE PREVIOUS OWNER OF THIS BIKE HAS INSTALLED WIRES TO BYPASS THE THERMO FAN SWITCH, SO WHEN THE MANUAL SWITCH IS THROWN THE FAN COMES ON.
SO I ASSUMED THAT THE THERMO FAN SWITCH WAS NOT WORKING AND REPLACED IT HOPING TO HAVE THE SYSTEM RUN AUTOMATICALLY AS IT SHOULD, BUT IT DOES NOT.

ANY IDEAS? WHAT ELSE COULD CAUSE THE FAN NOT TO COME IN WHEN REQUIRED, IS THERE ANOTHER SWITCH OR RELAY?

COULD THESE EXTRA WIRES BE CAUSING THE PROBLEM?

KIND REGARDS, Craig :???:

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Andrew
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#2 Post by Andrew » Mon Mar 26, 2007 5:12 am

Put the thermo switch in some boiling water and measure the resistance of the switch.
I've over-ridden the thermo switch as well, but it still works.
Andy (UK)
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Faster Faster !!!

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cb4265
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COOLING FAN NOT COMING ON?

#3 Post by cb4265 » Mon Mar 26, 2007 5:35 am

HI ANDREW,

SWITCH IS BRAND NEW, JUST FITTED.
COULD ANYTHING ELSE CAUSE THE PROBLEM?

CRAIG

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#4 Post by hybrid » Mon Mar 26, 2007 8:42 pm

I haven't looked at a wiring diagram, but it shouldn't be too complex.
The thermo switch probably makes/breaks the earth, so it should be simple enough to test.

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#5 Post by zalienz » Tue Mar 27, 2007 1:12 am

It is a rather simple circuit. Positive Power flow from the YPVS fuse in the fusebox goes straight to the thermo switch (and ypvs of course). You should be able to use a voltmeter and have battery voltage at the thermo switch, brown wire with the key on. From the switch through the blue wire to the fan motor itself. Fan motor has a black wire which goes to ground back to the battery. Check for power at the thermo switch, and at the fan motor when the switch is closed. Check for continuity on the ground side of the motor.

Keep in mind the thermo switch does not close until water temp is 208-221 degrees Fahrenheit. The old story (not mine) is that Yamaha did not switch on the cooling fan until absolutely necessary as when the fan was on, the charging system ran at a deficit. That would cause the battery to go dead in a rather short period if the fan was running, especially if the headlight is on. The charging system only puts out about 15 amps.

This is why a lot of guys would bypass the thermo switch and use a manual switch to turn on the fan sooner, keeping the engine cooler.

To test the thermo switch, rig a way to suspend it in hot water in a pan on the stove with a thermometer, and an ohmmeter to the connections. It should read infinity when open (below 208 degrees F.) and close to 0 ohms when closed (208-221 degrees F.)

Good Luck!
RZ500
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Whether you think you can, or you think you can't, either way, you are right -Henry Ford

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COOLING FAN NOT COMING ON?

#6 Post by cb4265 » Tue Mar 27, 2007 2:07 am

You may be on to something there with the temperature, but I let it get really hot, nearly upto the red zone, surely this would be time for it to cut in?
While riding it it did not get over hot, only while idling after the ride, waiting for the fan to cut in.

I will try to find exactly where these extra wires are attached and make a more informed thread if I don't fix it first.

God it was fun to ride for the first time though, stuff the greenies and their polution policies!
Nothing better than fresh TTS smell! Though I believe MOTUL even better!

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#7 Post by zalienz » Wed Mar 28, 2007 12:47 am

As I remember it wouldn't go on until the red zone.......not exactly what any 500 owner would want. Another reason for the manual switches.

I'm curious what the extra wires are for, one thing for sure, it's not the fan.
RZ500
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Whether you think you can, or you think you can't, either way, you are right -Henry Ford

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COOLING FAN NOT COMING ON?

#8 Post by cb4265 » Wed Mar 28, 2007 1:21 am

THE EXTRA WIRES ARE SPLICED INTO THE WIRES COMING OFF THE SWITCH TO ATTACH A MANUAL OVERIDE SWITCH TO, AT THE MOMENT THERE IS A MALE TERMINAL & A FEMALE TERMINAL AND YOU JUST JOIN THEM TO MAKE THE CIRCUIT AND THE FAN COMES ON.

I WILL MOUNT A SWITCH WITH A LIGHT SO IT IS CLEARLY VISIBLE AND ONLY USE IT WHEN IN SLOW TRAFFIC.
WHILE MOVING ALONG AT 60KM PLUS THE RUNNING TEMP IS IN THE LOWER THIRD OF THE GAUGE.

THANKS FOR THE INPUT EVERYONE, I THINK THE CASE IS CLOSED.

KIND REGARDS, CRAIG :smile:

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#9 Post by hybrid » Wed Mar 28, 2007 4:14 am

I will use my ECU to control the fan on my 500 project.

What is the recommended temperature to bring in the fan?
On my SP1, the fan comes on at 103C

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#10 Post by Twinsport » Wed Mar 28, 2007 2:44 pm

Hi there

Take a look in the old discussion:

http://www.rzrd500.com/500phpBB3/viewto ... ght=nissan

/Steen
If I had a signature, it would be good.

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