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View Full Version : Radiator fan almost always on - SV650S K2

ozborn
21-03-09, 06:20 PM
Hi guys.

The radiator cooling fan on my 2002 K2 SV650S is almost always on. Even when the engine's cold, first thing in the morning. It's just had a service but as it was the rare time the fan wasn't running, the mechanic couldn't find the reason for it.

Any suggestions about how I can fix this would be appreciated.

Best regards.

Jay
gettin2dizzy
21-03-09, 06:27 PM
Where are you located?
simesb
21-03-09, 06:29 PM
Any suggestions about how I can fix this would be appreciated.

Short in the switch?
the_lone_wolf
21-03-09, 07:04 PM
faulty thermostat?
ozborn
21-03-09, 07:05 PM
Short in the switch?

Thanx, simesb. Do you know where the switch is located? Is it on or near the fan?
ozborn
21-03-09, 07:06 PM
Where are you located?

Northamptonshire!
ozborn
21-03-09, 07:08 PM
faulty thermostat?

Cheers. Where would you say the most likely area for the fault is? In other words, what should I replace first, second, third...?
the_lone_wolf
21-03-09, 07:11 PM
Cheers. Where would you say the most likely area for the fault is? In other words, what should I replace first, second, third...?
the fan is running because it's getting power from the battery, there's a few things it might but to test the thermostat:

get a haynes manual

remove the thermostat and test it, all as described in the haynes

if faulty then replace it, if not then look somewhere else on the wiring diagram for the reason the fan is getting power, faulty switch/relay etc, i don't know the exact wiring
keith_d
21-03-09, 07:16 PM
Strangely enough I've got the opposite problem - the fan on my SK4 never comes on. Last night engine temperature hit 104C in traffic around Soho before I gave up and went home.

I bypassed the switch and the fan works fine, so I've ordered a new switch. You could try unplugging your switch and see if the fan still runs.

If the switch is faulty it might be worth contacting Mattglavin to see if he's still got the switch from the SK2 he's breaking.

Keith.
ozborn
21-03-09, 08:10 PM
Lone Wolf, I'll get a haynes manual.

Keith, I'll give your suggestion a try and contact Mattglavin if I need to.

Thanx for your help, boys. J
Sid Squid
21-03-09, 08:42 PM
faulty thermostat?
It's very doubtful that the fault lies with the thermostat.

OP: First are you sure the bike isn't running hot? How long do you have to have the bike running before the fan comes on?

Assuming it isn't running hot, do this:

On the radiator there is a screwed in brass switch with two terminals on the back of it in a two connector plug, with the ignition on and the fan running pull the plug off of the switch, if the fan stops then the switch is at fault. If it doesn't stop then there is damaged or wrongly connected wiring.
ozborn
21-03-09, 09:09 PM
Sid Squid.

The bike is certainly not running hot. As soon as I switch the ignition on, the fan's on. This could be first thing in the morning or after not using it for a while (even a couple of months over winter. I'm not that mad a rider!).

I'll try pulling the plug off the switch and see what happens to the fan.

Thanx Sidney!
gettin2dizzy
21-03-09, 10:01 PM
Do you have a temp gauge?
Sid Squid
22-03-09, 12:19 AM
Not unless an addition has been made - OP has a curvy = no temp gauge.
bris
15-04-09, 07:07 PM
Did'nt want to start a new thread for this so will revive this one.
How do I test the fan switch, my fan never comes on but after shorting the wires I know the fan works. I pulled the plug of the radiator and gave it a clean but still does'nt kick in (I let it get to 120) is there a test to see if it's the fan switch before I buy a new one.
yorkie_chris
15-04-09, 07:28 PM
Yes, short the switch out and see if the fan comes on.
Bluefish
15-04-09, 07:38 PM
Yes, short the switch out and see if the fan comes on.

lol
yorkie_chris
15-04-09, 07:40 PM
Ah b0llocks. Sorry! Didn't read that properly at all!

There's a section in haynes about it, can't remember if you can get away with boiling it in water with a test light on it or whether you need to use oil.

It certainly sounds like the switch isn't working though.
embee
16-04-09, 05:08 PM
This is what the curvey manual says

http://i258.photobucket.com/albums/hh268/Hi-vis/fanswitchSmall.jpg
Rocket
16-04-09, 05:47 PM
Nowt to do with the thermostat as Sid Squid rightly says. Replace the Thermo switch screwed into the radiator.
Luckypants
17-04-09, 09:12 AM
This is what the curvey manual says

http://i258.photobucket.com/albums/hh268/Hi-vis/fanswitchSmall.jpg

Good post Embee and for completeness, the pointy manual says same thing

EXCEPT

Cooling fan thermo-switch operating temperature
Standard (OFF-*ON): Approx . 98 °C (208 °F)
(ON-*OFF): Approx . 92 °C (198 °F)
bris
17-04-09, 04:19 PM
Good post Embee and for completeness, the pointy manual says same thing

EXCEPT

Cooling fan thermo-switch operating temperature
Standard (OFF-*ON): Approx . 98 °C (208 °F)
(ON-*OFF): Approx . 92 °C (198 °F)

Thanks for that but looks like a bit of a palava so got a second hand one off ebay for £7. Believe it or not a dealership wanted £46 for it, nearly chocked.