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Jay58's avatar
Jay58
Explorer
Jul 12, 2015

Blower Motor power wire getting very HOT

96 HR Endeavor, Freightliner chassis, power wire suppling 12 v. for selector switch (dash AC and heat and fan) got so hot it melted fuse box connection. replaced wire and fan several times (new) still same problem. direct wire 12 v feed lets fan run without heating wire.
When the selector switch is turned on the wires gets hot quick. (with 12v supplied to fan with seperate wire.)

Any ideas, didnt find any bare wire grounding out or loose connections, I think the switch could be bad so Ill order a new one to try.

:h
Class A

18 Replies

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  • 2oldman's avatar
    2oldman
    Explorer II
    Jul 12, 2015
    Jay58 wrote:
    have installed 3 new from Autozone and 1 new from NAPA its a standard Chevy blower motor.
    If you are referring to the fuses, it would seem they're too big. A wire should never get that hot. That's what fuses are for.

    Either that or somehow this wiring is bypassing any fuses.
  • Jay58's avatar
    Jay58
    Explorer
    Jul 12, 2015
    Ford was a waste on trying to find a replacement heater AC fan selector switch....I did find one online which I will order and install. Willl update this thread after I replace it.
  • Jay58's avatar
    Jay58
    Explorer
    Jul 12, 2015
    rgatijnet1





    rgatijnet1





    rgatijnet1 that makes sense, the fan speed selector wont change the fan,,,continuiously on high. Ill check that next.....Thanks for the info.....
  • Jay58's avatar
    Jay58
    Explorer
    Jul 12, 2015
    sch911

    when powered with a line from battery it runs fine and does not get hot. when the selector switch is moved to any position other than off the wire gets hot quick. turn the selector off and it gets room temp.
  • rgatijnet1's avatar
    rgatijnet1
    Explorer III
    Jul 12, 2015
    I assume that the fan switch is multi-speed. I would guess that the resister element in the speed switch has a partial short to ground.
    You can use a multimeter to check the current(Amps) draw of your fan but I would guess that it is drawing a lot more current when hooked up through the switch than when wired direct. If it does, this would indicate a bad switch.
  • Jay58's avatar
    Jay58
    Explorer
    Jul 12, 2015
    have installed 3 new from Autozone and 1 new from NAPA its a standard Chevy blower motor.

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