Cooling Fans Temperature Switch Test?

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Hubbskiboy
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Cooling Fans Temperature Switch Test?

Post by Hubbskiboy » Sun Sep 30, 2018 12:48 pm

I'm having a right palaver trying to get a fan switch that works.
The situtation is this - I have a total of 3 of the same switch.
One definitely works as it kicks in the fans about 3/4 of the way up the temp gauge.
One definitely doesn't work as it does nothing right up to the red line.
Not sure about the 3rd one which I bought 2nd hand from ts-parts-uk-jp (Japan spares) on eBay.
I rigged up a decent test rig by placing each one in a pan of water and slowly bringing it up to the boil.
I bought a dial thermometer which I know is pretty accurate as the water boiled at exactly 100 degrees.
I tested each switch with both a circuit continuity tester and also a multimeter.
Got zero readings on both devices for all 3 switches.
Not even a slight variation on the multimeter right up to about 108 degrees C.
What the hell am I doing wrong?
Aren't these switches supposed to kick in about 95 degrees?
I've fitted a bypass switch on both my bikes because of these little buggers.
They just don't want to play ball.

Suzuki416
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Re: Cooling Fans Temperature Switch Test?

Post by Suzuki416 » Sun Sep 30, 2018 10:02 pm

From what I remember the system is pressurised and so a higher temp is attained. This also means that the system should never boil.

moforockband
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Re: Cooling Fans Temperature Switch Test?

Post by moforockband » Sun Sep 30, 2018 10:16 pm

gk73 93-99degrees off to on. 86-92 degrees on to off off
gsf400 bandit off to on 117 degrees. on - off 110 degrees.

Make sure you use croc clips and are on the beep setting (diode test - its easier).

My 73a only comes on fan real near the red

Hubbskiboy
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Re: Cooling Fans Temperature Switch Test?

Post by Hubbskiboy » Sun Sep 30, 2018 10:50 pm

Hi Mofo.
So as I understand it, and correct me if I'm wrong. ;)
I'm sure that the operating temp for my bike is the same as a GSF400 bandit as they are essentially the same engine.
And you're saying that the fan switch shouldn't kick in till the coolant reaches 117 degrees C?
The water I'm boiling in a pan will never reach that temperature, which is why none of the switches are doing anything.
Correct?
So the only way to test these switches is to use some kind of pressurised system, which of course I don't have in my garage!
I've been looking at 52mm (or 2" if you like) aftermarket water temperature gauges with some actual numbers on them, so I can get a rough idea of the temp of the system.
Why didn't Suzuki do this in the first place? Arrrrrggghhhhhhh!!!!!!

moforockband
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Re: Cooling Fans Temperature Switch Test?

Post by moforockband » Sun Sep 30, 2018 10:58 pm

Doesn't need to be pressurised. Its fine to just use a glass thermometer.
The reason I put the difference in the thermo switches is that the engines are pretty much the same across B400, 73a and 76a, but depends on which switch you may have, because they will all fit I reckon.
117 degrees seems really high though, probably just to get the wheezy old bandit to run properly :D
Cant believe you're having so much aggro with it!
Buy a thermo gun off ebay and measure the actual radiator temp, cost about a tenner

moforockband
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Re: Cooling Fans Temperature Switch Test?

Post by moforockband » Mon Oct 01, 2018 11:56 am

Just re-read your 1st post. When you say you get zero reading, you mean 0 ohms?? Because if you are that is correct for the switch. The switch goes full resistance ie (open line) when it has cooled off.
The problem may be with your bikes wiring.

Hubbskiboy
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Re: Cooling Fans Temperature Switch Test?

Post by Hubbskiboy » Tue Oct 02, 2018 11:38 am

Nah Mofo.
When I said Zero readings I mean't nothing changed on my Multimeter.
Granted it's misleading when I said 'Zero' so just ignore that.
I wonder how much coolant will come out of the system if I swop the switch out.
Not a lot I suspect as it's almost at the top.
Just ordered the cheapest switch I could find on eBay.
https://www.ebay.co.uk/itm/173261300152
If this works it'll be a result.
Can believe you can get a switch from China for £4.65, but the OEM part is £70!
I'll keep an eye on it once it's installed so don't worry. ;)

gazza49
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Re: Cooling Fans Temperature Switch Test?

Post by gazza49 » Tue Oct 02, 2018 7:48 pm

quite a few parts on aliexpress,including this temp gauge
https://www.aliexpress.com/item/Motorcy ... 92338.html?


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