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Discussion Starter #1
My cooling fans started kicking in at 1/4 temp, where it used to be at 3/4 temp.
Any ides why it started doing this? How to fix?
Thanks,
Phil
 

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Either the fan temperature switch is too sensitive, or the temperature gage is reading low. If you have an independent way to measure the temperature of the coolant, see what the actual temp is when the fans start.

OK, I've done the easy part... :D Others will offer better advice, I suspect.

Good luck.
 

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not sure about what drives the gauge, and I'm pretty sure a thermal switch activtes the fans. the fans are coming on, so it sounds like the switch is working, so it could be an indicator problem

just to make sure, what's your coolant level like?

might be a pressure leak, thermostat or even a water pump failure if the temp switches are in a different part of the coolant system from the indicator sensor. I wish I had more time to look into this, but I gotta get going to work.
 

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for this, I wish I had a wiring diagram instead of a repair manual.

I found four (?) temp sensors, one of which is the Air, so that's out. there is a cyl head temp, water pump temp and coolant temp.

I could swag that the cyl head temp is for the idiot light (?). so that leaves a 50/50 (~) choice for the fans and gauge.

I'll keep looking, if anyone can point me in the right direction for a wiring diagram, that would be great ;)
 

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Discussion Starter #5
Thanks for the feedback. I was wondering if it hurts for the fans to run for a long time? Where they ment to run continueously, or will they be damaged.
I would like to go for a ride this Memorial w/e but if I am going to burn up the motors?
Hope to get to the bottom of this by Saturday (5/23/09) before the dealer closes for the w/e.
Phil
 

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If you pull the side panel and look at the wiring for one of the fans it should either be a switched hot lead ar a switched ground for the fans. If it's a switched ground you will show a hot lead whenever the ignition is on and you will show zero conductivity to ground unless the cycle is hot enough to run the fans. With a switched hot lead you will have conductivity to ground and lack of voltage unless the fans have kicked on. You could also warm it up until the fans kick on and then disconnect the sensor wires one at a time to find the right one. Generally speaking the ground wires will be brown in color. Good luck.
 

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Check coolant level and it also could be the cap has gone bad.
 

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2005 K1200LT
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The fan relay is provided a ground from the Motronic to activate the fans. It is anyone's guess which sensor actually FEEDS the trip point to the Motronic.
 

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The Motronic gets it's temp input from the sensor located on the aft end of the head. The gauge gets it's input from the sensor on the water pump.
 

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2011 R1200RT
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simoncharles said:
How many fans has the 2005 and up LT got, one or two ?. Only one is shown in the parts sites. Only one 7,5 amp fuse as well.
2 fans on all years LT, one on each side, or one per radiator since there is a radiator on each side.
 

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Could an obstruction cause this? I was sitting on the ground in front of my LT one day and noticed a plastic bag had blown up onto 1 of the radiators, completing blocking it. I didn't notice the fans running sooner or longer than usual, but it couldn't have helped to have that.
 

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Thanks Zippy. Why do some posts claim that each fan has it´s own individual electrical circuit with it´s own fuse when my 2005, only, as far as I can see, has one ?.
 

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Phil_Blackstone said:
My cooling fans started kicking in at 1/4 temp, where it used to be at 3/4 temp.
Any ides why it started doing this? How to fix?
Thanks,
Phil
Is the front of the rads blocked up with bugs and crap , if the air aint getting through it,s gonna run hotter . Regards numbnuts in blighty.
 

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2005 K1200LT
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simoncharles said:
Thanks Zippy. Why do some posts claim that each fan has it´s own individual electrical circuit with it´s own fuse when my 2005, only, as far as I can see, has one ?.
The bikes prior to 05 did have two fuses and two circuits but only one relay. The fuses were after the relay. On the 05 and up the fuse is before the relay and the fan ciruits tie together after the relay.
 
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