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Radiator Fan Manual Switch


TY 4 Stroke Junkie
Oct 27, 2004
N53.486 W59.860
Looking to install a manual override switch on the radiator fan on my 2006 VK Pro. I believe user Air19 has done this in the past but I am not certain he documented the wiring. I will get my hands on the wiring diagram and have a go at it, just wondering if anybody had any input before I tackled it.

Here is the wiring diagram


  • VK10L Wiring Diagram 2006 - 1 of 2.pdf
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  • VK10L Wiring Diagram Symbol Legend - 2 of 2.pdf
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if memory serves, @air19 had a 2nd rad with the manual switch for it on his vk pro.

think it was covered in this thread https://ty4stroke.com/threads/grooming-in-vermont-with-08-vk-pro.50901/page-18

Thank you for helping me dig up that thread, I actually corresponded with air19 a fair bit many years ago when he was performing some of these mods, but that was 10+ yrs ago now, maybe even closer to 15. Wow.

Thanks to a great electrically inclined friend of mine, we sat down and reviewed the wiring diagram for the VK pro and the relay that controls the fan motor coming on and off. I am going to parallel a switch across the left side of the relay #15, which will still permit the temperature-induced function to work.

Using a three wire switch (+, -, load) I will break into the Br/G wire coming into the relay (+), then tie the load pin into the L wire. I will tie the (-) pin on the switch into some sort of chassis ground point nearby to allow the indicator light to come on when I have the fan manually engaged.
Spent some time sizing things up last night, could not find relays. I am being told that they are above the footwell areas. Any truth to this? I'll check tonight either way...
well that is where yamaha put them on the apex and vector sleds. on apex they are above left foot behind the plastic.
Did some research, got well into this job today.

Three pin switch, load, +ve, -ve

Fan relay is above brake side footwell, closest to tank of the two.

To install a manual over ride switch, while still maintaining the sleds ability to start the fan automatically if temps creep high and you weren't using the sled to groom, you tie the switch between the Brown/Green wire before the relay, and the Blue wire after the relay, i.e. the blue wire on the two wire connector that feeds the rad cooling fan.

The Brown/Green wire goes to the +ve terminal, the Blue wire goes to the Load terminal (middle), and the other terminal goes to ground anywhere at all. I used an empty M6 nutsert ahead of the fuel pumps on the deltabox chassis member for my ground. To be clear, you do not cut off any wires, you simply strip about 1/2" of insulation off the blue wire and the brown/green wire and join your new wires in there with solder and then protective sleeve/heatshrink/elec tape.

Basic pics below:


  • wiring diagram vkpro switch.jpg
    wiring diagram vkpro switch.jpg
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  • mock up.jpg
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