03 640 adv fan switch

Discussion in 'Thumpers' started by 98rxcmi, Apr 16, 2006.

  1. 98rxcmi

    98rxcmi Chrome+Paint=Garage bike

    Joined:
    Sep 29, 2005
    Oddometer:
    126
    Location:
    03 640 Adventure
    Can someone tell me how many bars on the temp guage you see when the fan kicks on. Mine got 2 bars from the top and it never came on. The red light never came on...but I was too chicken to let it go any higher. I jumped the switch with a short section of wire and the fan works so it has to be the switch.

    Thanks
    #1
  2. gunnerbuck

    gunnerbuck Island Hopper

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    I also have an 03 Adventure and like you the fan has never kicked on. The engine runs at a steady 4 bars and only a couple of times has it jumped to 5. I checked the fan to make sure it was working and it was o.k., so either the sensor isn't working or the engine has never been hot enough to kick the switch. According to the manual 5 bars is 90-99 c {194-211f} which still, I'm assuming, isn't hot enough to kick the sensor switch on to activate the fan. Have any 640 owners had the fan kick on at 5 bars? Thinking about it ,the upper end of 5 is near boiling so the the fan should be kicking on before 6 bars is reached, but then how accurate is the display unit anyways? Maybe some Adventures display a steady 3 bars at operating temp. Anyways , it may not be a bad idea to wire in a manual switch to the fan just in case the sensor switch is faulty, probably something in the index on that.
    #2
  3. creeper

    creeper Still alive...

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    My fan comes on after the fifth (194F) bar has lit and just before the sixth (212F) bar lights... so depending on which you believe to be accurate, the thermo switch (185F switch point) that turns the fan on, or the bar temperature indicator, my thermo switch is about 10 degrees late, or the indicator is 10 degrees early.
    Either way, it's proven to be all fairly consistant in it's inaccuracy, and I've never seen the seventh (230F) bar light up, nor have I had the radiator cap open (248F) to release pressure.

    Since switching to a 50/50 mixture rather than the 60/40 mix of antifreeze and water about 15 months ago, I think the bike runs a bit cooler, as it very rarely runs above the fourth (176F) bar anymore.

    C
    #3
  4. Drif10

    Drif10 Accredited Jackass

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    I run a lot of tight woods with mine, and felt that the fan came on too late, so I wired a switch up on the dash and when I get into the tight stuff, flick it on and the guage stays steady @ 3 bars. YMMV. :dunno
    #4
  5. creeper

    creeper Still alive...

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    How you got that wired Drifty... as a bypass or as the only way the fan comes on?

    C
    #5
  6. meat popsicle

    meat popsicle Ignostic

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    Oddometer:
    14,339
    Location:
    Circumlocution Office of Little Dorrit
    Badmunkie's wiring diagram for a fan switch HERE; I thought there was one other but I can't locate it.

    Fans in general:

    So the easiest way to check the fan is to let the idiot light come on so you know for sure you are in the temp range where the fan MUST be on. It is supposed to come on much earlier, so try this:

    1) let the bike idle in the driveway until the light comes on
    2) did the fan kick in much earlier?
    3) when the light comes on hit the kill switch but leave the bike on
    4) is the fan on?
    5) last try, use a bit of wire to bypass the thermostat as mentioned below.
    PS - did you check your coolant level?

    Or you can use the troubleshooting method (mentioned above):
    IMO coolant display legend on page 10 of the english section of the 2003 640a manual. Too bad they didn't translate it into oil temps...
    #6
  7. gunnerbuck

    gunnerbuck Island Hopper

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    Hey Drif 10 , how many bars were showing when your fan finally kicked on? What about on your 03 meat? It would be kinda nice to see what the average fan kickon guage reading is, I think 98 RXCMI is looking to see if his functioning properly by comparing to other results . I'll let mine go up to 6 to see if she kicks on, if not I guess I'll wire in a switch. Like Creeper says there is a 10 degree discrep. and probably the guages that read a steady 3 bars as normal operating temp kick the fan at 5 bars and the ones that run at 4 kick at 6 bars.
    #7
  8. gybeman

    gybeman Been here awhile

    Joined:
    Apr 7, 2003
    Oddometer:
    639
    Location:
    Ontario, Canada
    2 bars showing if moving normally. 3 if its slower or hot out. Fan comes on at 4.
    #8
  9. meat popsicle

    meat popsicle Ignostic

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    It's been awhile since I checked or had it come on, but I think mine was operating as the manual showed - it should be on by 5 bars. Of course I have no idea if your bike's temp display works the same way as my model. So I don't think an average 'fan on' temp display reading would be appropriate.

    Here is the 03s factory calibration from the owner's manual:
    [​IMG]
    #9
  10. gunnerbuck

    gunnerbuck Island Hopper

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    My fan finally kicked on thru the sensor for the first time yesterday. Was doing some tight trailriding { lotsa slow tractor stuff} and the fan kicked on a couple of times while the guage was in the five bar zone, at no point did it reach six.
    #10
  11. 98rxcmi

    98rxcmi Chrome+Paint=Garage bike

    Joined:
    Sep 29, 2005
    Oddometer:
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    Location:
    03 640 Adventure
    I got it to kick on (the fan that is) this weekend. I was on the second bar from the top. When it did it rapidly went back down to 3 bars from the top. The red light never came on. Sure wish I could buy a switch that came on 20 degrees cooler. I haven't found it yet
    #11
  12. gunnerbuck

    gunnerbuck Island Hopper

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    Looks like your fan kicks in at about the same reading as mine, my engine wasn't to terribly hot , no boilovers or steamshows with the rad cap pressure relief popping. I am satisfied with the way the system is working on my machine as is but I may still add a manual switch just in case.
    #12
  13. meat popsicle

    meat popsicle Ignostic

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    As I recall synthetic oils are stable to temps far in excess of the ~200 degrees that triggers the fan (I think that is still marginally safe with dino oils, but I will have to dig up the discussion - unless its indexed?).

    But perhaps you have other info and could say why you want the fan to kick in sooner? :ear
    #13