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Monday, June 02, 2014

Electric Fan

Howdy, I have an electric fan in front of the radiator in my 1995 GMC K2500 Suburban.  Yesterday I hauled a trailer weighing about 7,000 lbs.  It was a hot afternoon and the truck temp went to about 230ยบ.  When I shut the ignition off the electric fan went off too.  When I turned the key on but not the motor the fan came on.  I think the fan needs to come on when the motor is hot without the key on, right?


  1. Yes that is what it supposed to do unless

    It is wired direct to the ignition some how that is the only way it will come on and go off with the key

  2. The fan is supposed to have 12Volts on it all the time with the ground wire going to a temp switch on the motor that turns it on when its hot.

  3. Yes and No.

    Yes it should be on if the temperature is high but if the coolant is not being circulated at the same time it would only cool the radiator itself.

    That would not help to cool the engine at all!

    Also if the fan remained on and failed to shut off when it was cool enough you would go to start the truck and have a dead battery.

    OR if something failed you might end up with a fire!

    That is why I say Yes and No.

  4. I believe some of the earlier implementations of electric radiator
    fans had this problem and they made changes to the system so that
    couldn't happen.

    Maybe that only happened on some brands/models.