Radiator Fan Keeps Blowing Fuses

Posted by jakvett, Jul 17, 2011
Maintenance & Repairs - Oil choices, timing belt, setting timing, CV boot replacement, alternator servicing, fuse/relay checks, and other basic maintenance, repair and diagnosis discussions.

  1. jakvett

    jakvett Probationary Member

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    I have the flex-a-lite 325 slimline fan system in my 99 GST. I was cruising down the freeway about 65 for 20 minutes or so with no previous cooling issues then out of nowhere the check engine light came on, and the water temp was creeping up. I start up DSMLink to see the water temp is around 240. I blasted the heat until I could safely pull of the freeway (brought it down to 210 fairly quickly, and the check engine light turned off). Once I was stopped, I turned the car off, and checked the fuses. The 30 amp fan fuse was blown, and the passenger side fan smelt like burnt electrical components. I babied it home keeping the heat blasted, and monitoring the water temp on DSMLink. It stayed around 200-210 the whole way.

    Once I got home I tested both fans by spinning them with my hand, and the passenger side fan spun somewhat harder then the driver side fan. I then wired each fan directly to the battery to find the driver side fan worked fine, but the passenger side fan wouldn't spin at all. Okay, dead fan motor. So I pull the passenger fan out of the car, and replace it with the driver side fan. I replaced the 30 amp fuse, and, with the AC/defrost off, started the car up. The fan turned on and I was good to go. I let it warm up, and starting driving again. I cruised at 65 for about an hour then the water temp crept up again, and sure enough blew the same fuse. I'm guessing it's shorting somewhere or maybe there was an issue with the second fan not being there, but I'm not sure where to start looking. I haven't checked the second fan to see if the motor in it is now dead.

    TLDR - passenger side fan died, blew 30 amp fan fuse. Removed passenger side fan and replaced it with driver side fan. Ran fine for an hour then blew the fuse again. What now?
    #1
  2. tenn-gsx

    tenn-gsx Proven Member

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    Check the wiring to the fan in question. You may have problems there from the fan shorting and melting the wire insulator.
    #2
  3. luv2rallye

    luv2rallye DSM Wiseman

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    How did you wire up these fans? You may have wired them wrong.
    Try unplugging both fans and the 30A fuse. Now touch the leads of a 12v incandesent (not led) light (headlight, stop, turn, dome) in place of the fuse. If it goes on you have a short (or something drawing power). If not on, replug in fans one at a time, and both together and retest. Light should not go on or short.

    Shorts sometimes end up being in the mass of wires under the engine fusebox (disconnect battery if you are going to unbolt it and look). But thats the last resort - look elsewhere first.
    Last edited: Jul 18, 2011
    #3
  4. Mackadoches

    Mackadoches Awaiting Email Verification

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    Sounds like wires are crossed somewhere especially if you smelled something being burnt. The insulation may have been fried on a few of the wires and may be touching. This will def cause your fuse to pop and most likely melt it. If that is the case check the wires connecting to your fan plug.
    #4
  5. Black Widow97

    Black Widow97 Supporting Member

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    As stated check all wiring, you could also try checking the fan to see if it is easy to turn. If it is not it could be causing an excessive load on the circuit causing the fuse to blow. It is unlikely, but I have seen it happen.
    #5
  6. jakvett

    jakvett Probationary Member

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    The fan turns easily, and it doesn't smell like burnt electrical like the other one did. I suspect a short somewhere. I'll look around.
    #6
  7. jakvett

    jakvett Probationary Member

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    I wired the other fan directly to the battery, and it spun for a half a second before blowing a 20 amp fuse. How possible is it that it would be fine with a 30 amp fuse wired directly to the battery (for testing of course). I figure if it blew the 20, it would blow a 30 shortly after, but don't what it normally draws when it's running. If that's the case, I'm gonna call time of death on the second fan and order a new set.

    Also, I bought the car with the fans already installed so I don't know how long they've been installed, but I would guess a few years. How long do these fans normally last?
    #7
  8. Black Widow97

    Black Widow97 Supporting Member

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    Longevity of the fans really depends on driving conditions. Hot or dirty/dusty conditions will most likely shorten the life. It also depends on the quality of the fans.
    #8
  9. scott90gsx420

    scott90gsx420 Proven Member

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    Weird i have this same issue... But my driver side fan is the one dying... I suspect mine from being so close to the exhaust mani that it melts the wires inside the fan as ive pulled the fan apart, and rewired it.

    The confusing thing is that the POWER wire inside the fan is always the one that melts... Once it melts, it blows the fuse..
    Then i can throw a new fuse in there and the passenger side fan will start right up and stay on for an undetermined period of time(as in it just stays on it has never blown a fuse..).....
    Oh and it blows it on a 30A fuse or even a 40A...Thoughts??

    Sorry not trying to thread jack just figured id save site space and post on hear haha ;)
    #9
  10. SeanCollins

    SeanCollins Proven Member

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    I had a similar issue with my FAL slimlines. But it was popping my ignition fuse any time the fans would turn on. Ended up switching to a pair of 10" slim fans from auto zone and wired to a switch to fix my problem. Once I do a wire tuck I will have them hooked up properly but until that time comes I am just fine.
    #10
  11. luv2rallye

    luv2rallye DSM Wiseman

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    This is why you must use a relay for the fans and wire the relay's main power through the fuse for the fans (30A fuseable link 2) - NOT the Ignition fuse :nono:
    #11
  12. SeanCollins

    SeanCollins Proven Member

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    Well the guy I bought it from had them wired that way. I'm still working out bad wiring.
    #12
  13. scott90gsx420

    scott90gsx420 Proven Member

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    Bump.. Need some help guys pulling motor and stuff tomorrow for my broken carrier barring bolts and id like to fix this while motor is out..
    #13
  14. phunny

    phunny Proven Member

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    One of your fan motors is blown. Spinning them by had will do nothing at all.
    #14
  15. scott90gsx420

    scott90gsx420 Proven Member

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    If its the motor then why can i fix it have it work for three hours then it goes again??? IDK if that was ment for me or not but ya LOL??? By the way i have pulled the fan COMPLETELY apart like 4-5 times now to fix this issue.. And every time the power wire comes out all hard and melted looking..

    And its only the first part after it passes by one conductor it no longer melts... CAN the heat be causing this or am i looking in the wrong spot..

    By the way i have NO heat shields there were none on the car when i bought it.. I wrapped the o2 housing and it seemed to help a bit but the fan still dies.. Looking to find or make a heat shield for ex. mani when motor is out this weekend.
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  16. luv2rallye

    luv2rallye DSM Wiseman

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    Heat shields are necessary to protect fans and alt.
    But also measure your battery voltage with car running to make sure it's not too high (should be 13.5-15.5v, ideal is 14.4v) and burning your fan out.
    Do you have aftermarket fans and how are they wired?
    #16
  17. scott90gsx420

    scott90gsx420 Proven Member

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    Well my safc allows me to watch my battery voltage.. It is always 13.9--14.5.. it never gets higher or lower then that... Unless cars off then its lower but i doubt that makes a difference.. Yup aftermarket 12's that came with the car and there wired to a toggle switch straight from the battery..

    The reason im thinking the heat is that its ALWAYS the driver side fan.. Which is really close like 2inches away from the turbo and exhaust mani..

    The passenger side fan has never died.. And when this problem first started i bought a Autozone fan and ran that for a while.. It never blew the fuse then either..

    But i noticed the wires on that fan getting really hard too.. And the fans CANNOT be touched when the cars been ran but i can touch the passenger side one..

    I then decided the Autozone fan was a last resort as it pulls like a bit over half what the other fan does.. So i fixed the other fan because it flows so much better but i keep blowing fuses and its really annoying LOL..
    Im thinking while the motor is out im going to duct some stuff and see if that helps with the cooling aswell..
    #17
  18. luv2rallye

    luv2rallye DSM Wiseman

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    I agree it sounds like the exhaust mani is what's burning your fan wires. It probably burns the insulation off enough somewhere to touch metal and then the fuse blows.

    BTW power to the fans should NEVER come from a toggle switch inside the cabin. That's dangerous with the current amount and what would happen if a short developed in that wire. The toggle should operate a relay in the engine compartment which supplies the fan power through a fuse from the battery.
    #18
  19. scott90gsx420

    scott90gsx420 Proven Member

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    So what do you think would be the best thing to do?? If you think it should be rewired tell me haha.. I dont wanna do anything that would put the car at risk of fire or anything.. And if i should rewire it what would be the best way i like having control of when they come on LOL..
    #19
  20. luv2rallye

    luv2rallye DSM Wiseman

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    I assume you want both fans to be on and off together. So leave them wired together but run the power for them both off the larger blue-red wire in the original passenger side fan connector. That will use the original radiator fan relay which should be able to handle both fans. Then on your toggle switch connect one side to ground and the other side to the green-black wire on any one of these: a) thermo sensor on the radiator bottom, or b) radiator fan relay, or c) air conditioner control unit. When the switch is off the radiator thermo sensor will control fans (this is stock). When the switch is on the fans will be forced on. In either case they will still go off when the ignition key is turned off and be fuse protected.
    #20
  21. luv2rallye

    luv2rallye DSM Wiseman

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    Maybe you should replace the wires coming out of that fan with the type used in stove/furnace - has extreme temp insulations (get at Home Depot). Use 14 gauge (minimum) for only 1 fan's current going through it, 12 gauge (minimum) for both fans current going through it.
    #21
  22. scott90gsx420

    scott90gsx420 Proven Member

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    All the original wires that lead to the fans are gone.. One of the previous owners cut them all the way out when they switched to this setup.. Asshole even CUT all the A/C lines so even if i wanted to go back to A/C i cant haha.. So all the connectors and plugs as well as all the wires to them are gone..

    Also i have a 30amp fuse right off the battery in-between the toggle switch and battery.. Il look into the insulated wire as well i still havent got the motor out its sitting there waiting for me to get the lift and pull it..

    Im going to look for a stock heat shield and if i cant find one im going to fab one and let someone weld it..

    Then when everything goes back together it will either work because the heat isnt melting the wire anymore or it will continue to do this because of the fan being crap LOL.. In which case il just scrap it and put my Autozone in there and call it good..
    #22
  23. luv2rallye

    luv2rallye DSM Wiseman

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  24. cdone

    cdone Probationary Member

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    I'm having the same issue, but I have a 1g metal fan driver side. I think my issue is I connected the plug in reverse! So I'm going to switch it around and drive around see if it blows. I had to modify the 1g fan female end to fit the 2g male end.
    #24

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