Fan Switch

Discussion in '1st & 2nd Generation 1983-1989' started by 86viffer, Aug 4, 2005.

  1. 86viffer

    86viffer New Member

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    I had the local shop replace the thermostat in my '86 VFR750, and when it first came back, the fan was working fine.

    Now, it has stopped working completely, and the bike is overheating at low speeds in traffic.

    I noticed a wiring harness hanging below the fairing on a ride the other night, and happened to find 2 wires unplugged and I'm hoping they might be for the fan.

    Does anyone happen to know where the fan wiring would be on this year/model?
     
  2. mozilla.v4snob

    mozilla.v4snob New Member

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    yo viffer. I have same bike. My fan works great but the bike still gets hot in traffic. It's old and the design isn't that great for dissipating heat. There are usually 2 wires connected to a temp sender on the left side of your radiator near the bottom. If those wires are disconnected, your fan will definitely not work. The wiring for the fan should come around the right side of the frame on the bottom and then attach directly to the back of the fan motor. Let me know if that doesn't help or tell me where the wires are hanging and what color they are. Pix would be helpful too. Good Luck.
     
  3. 86viffer

    86viffer New Member

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    Thx Moz, I'm going to go check to see if I can locate the harness you mentioned...it doesn't sound like the one that was hanging, so now I'll go check that.

    If I don't have any luck, I'll get the camera out and post up some pic's.

    Thanks again.
     
  4. 86viffer

    86viffer New Member

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    OK...chalk this one up as stupidity on my part...

    Pull the upper fairing off to get a better look at the wiring...after looking it over a few times, came to realize that what had been disconnected was the parking/directional lights. ::)

    So, in a flash of brilliance, I figure, 'Hey, I'd be willing to bet there's a fuse for the fan!'...sure enough, pull the fuse cover and found one blown 10 amp fan fuse. :-[ Thankfully there was a spare in the panel, installed and fan works fine.

    Ugh.
     
  5. bwsmith

    bwsmith New Member

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    hey, all,

    i have an '86 750 interceptor and have had the same trouble with the fan failing to come on, and the coolant boils out onto my right foot at stop lights. i just rigged a three-dollar switch from radio shack, and now i can activate it myself. problem gone.

    bryan
     
  6. vfromey

    vfromey New Member

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    yep, these oldschool hondas have thermostats that wait too long before turning the fan on. and most of the time they eventually fail and stop working. so i did the fan bypass switch as well. works like a charm. turn the fan on whenever and it stays cool.  
     
  7. Nailer45

    Nailer45 New Member

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    I wired in a toggle switch to my fans so i could turn them off or on when I
    thought the bike was getting to warm...It worked great for me ..
     
  8. MontanaHigh

    MontanaHigh New Member

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    I also boiled over due to a blown fuse. The only indication that the fan is even running is it's whirl. I wired a small green light into the "fan on" loop and set it in the gap between the dash and the fairing. (upper right corner) After watching it for a season's worth of rides and knowing the approximate temperature that it should light up, at least I know that the fan is getting power and "should" be on. I'm planning on doing the same thing on my Y2K. Check my "Photo Gallery" for a photo of its location.
     
    Last edited: Jun 16, 2006
  9. SLYDER

    SLYDER New Member

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    Does anyone have a wireing diagram of how to best hock up a fan switch? Do you bypass the fan relay? If the thermostat switch @ the bootom of the lower rad is dead should you still replace it if you are putting in a switch? Same for thermostat itself?

    My thing is that the fans will not come on but tested the motors and they do work. Followed the reapir manual and by bypassing the thermostst switch the fans should come on but they don't. It then says to check voltage and fuses and open circuits. All fuses are good, but I guess if the relay is dead then they are not getting any power, right?
     
  10. SLYDER

    SLYDER New Member

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    I found the problem to be the thermo switch at the bottom of the lower rad. The dealer wants $90 for it, I said good luck. Can I use a toggle switch to bypass the thermoswitch without causing any further problems?
     
  11. MontanaHigh

    MontanaHigh New Member

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    The only problem I can think of is not remembering to turn it on. With thermostats and relays it's all automatic at a certain temperature. If you watch the temp gauge and always turn the fan on, I can't think of a really good reason to spend the $90. Check Ebay for a used switch or if the price is right the entire lower radiator.
     
    Last edited: Jul 2, 2006
  12. 5891Jonathan

    5891Jonathan New Member

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  13. Outlawz24

    Outlawz24 New Member

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    Do you leave the thermoswitch plugged in when adding a toggle switch or does the toggle switch replace the thermoswitch...im getting tired of having to ride full out for about 20 mins just to keep my bike from boiling over. Alot of the riding i do in group rides is in town and usually at regular road speeds. I would rather the ability of starting the fans the moment the guage starts to rise.
     
  14. masonv45

    masonv45 New Member

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    Just a note: these bike do like to run hot - they're supposed to. Running the engine at too low of a temperature can hurt efficiency.

    If the bike is overheating, then something is wrong. Wiring in a bypass switch just masks the problem.

    Typical problems . . .

    1. Thermostat needs replacement (may need new O-ring)
    - Stant 13868 (Drill out brass rivet)
    - NAPA #101 (Drill out brass rivet)

    2. Fanstat needs replacement (May have to change electrical connection)
    - Wells SW504
    - GP Sorensen 40-5001
    - Borg Warner TFS500

    3. Radiator needs cleaning
    - Used 1/4 bottle of Lime Away and water, which is basically phosphoric acid, to flush entire cooling system. Fill radiator, plug and wait several hours. Flush THOROUGHLY. Note that CLR or Lime Away will destroy a stock fanstat. So either use a rubber stopper to block it off, or have a replacement handy. (Note, thermostat switch not affected)

    4. Hose split sucking in air
    - replace all hoses specifically the coolant reserve bottle hose

    5. Radiator cap needs replacement
    - Stant #11227
    - Perolator RR-27
    - Any radiator cap from a 96 Nissan Altima
     
  15. eddievalleytrailer

    eddievalleytrailer Member

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    I put a fan switch on my '83, and kept the thermo. switch in tact. That way, if I forget to turn it on, it'll do it automatically. If I see heavy traffic ahead, I just turn it on.
     
  16. speed

    speed New Member

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    yes i wired the same switch on my 86 vfr750f and no problem sence all thow i did have to change the thromastat once ?
     
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