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Thread: Blower Motor Problems - Testing/diagnosis

  1. #1
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    Blower Motor Problems - Testing/diagnosis

    So, my blower motor stopped working. I can hear the BCM clicking when turning the fan off and on. Tried hitting the BCM - no luck.

    Removed connector from fan. If I hook a ground up to the connector for the Brown/red stripe and then positive to the Red/White stripe the blower works.

    I can even connect the Red/white stripe wire to the motor and leave the ground connected separately and the motor works but no speed control.

    So, is it the BCM because the ground side is not connected and that is the side that controls the speed? In other words variable resistance from the controller?

    Please help

  2. #2
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    I believe the motor has hot 12 volts all the time and ground is varied. Sounds like the module behind the passenger cam cover, right under the heater core hoses.
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  3. #3
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    Yes, good diagnosis. Blower motor works then the BCM has failed and on yours it is not the high speed relay that normally fails.

    I would try and get a ford product.... dorman is crap.

    That harness that plugs to the BCM is about 2 foot long after its unplugged, no need to actually remove the BCM if you wanted to test the new part to fix it.
    I actually burn thru a few of these on my cars, it is what it is.
    And one car the BCM is strapped to the large AC line to test the other ones i have.

    Good luck
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  4. #4
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    Probably the BCM.
    “When you can’t make them see the light, make them feel the heat.”
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  5. #5
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    Time for a BCM .....

  6. #6
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    Did you test the resistor pack on the firewall? Maybe I missed that

  7. #7
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    Quote Originally Posted by Mackdombles View Post
    Did you test the resistor pack on the firewall? Maybe I missed that
    Huh? Resistor pack?
    “When you can’t make them see the light, make them feel the heat.”
    Ronald Regan

    "The only way to deal with the Islamic State - these blood thirsty, blood-drunken, terrorists -
    is to kill them, keep on killing them, until you kill the last one, then you kill his pet goat."

    Lt. Colonel Ralph Peters

    “Be polite, be professional, but have a plan to kill everybody you meet.”
    "I come in peace. I didn't bring artillery. But I'm pleading with you, with tears in my eyes, if you **** with me, I'll kill you all"
    General James Mattis




  8. #8
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    Quote Originally Posted by Greg View Post
    So, my blower motor stopped working. I can hear the BCM clicking when turning the fan off and on. Tried hitting the BCM - no luck.

    Removed connector from fan. If I hook a ground up to the connector for the Brown/red stripe and then positive to the Red/White stripe the blower works.

    I can even connect the Red/white stripe wire to the motor and leave the ground connected separately and the motor works but no speed control.

    So, is it the BCM because the ground side is not connected and that is the side that controls the speed? In other words variable resistance from the controller?

    Please help
    First,
    Turn on the key and the blower control to high.
    Then go out and check with a multi meter if the motor has at least 12v to the power wire, and make sure the ground wire has a good ground with little to no resistance to battery ground. If it is missing power, check blower fuse first then wiring. If it has no ground, locate the resistor pack behind the pass head on firewall.
    The orange/red stripe wire is the control wire. It will vary in resistance to ground as you change settings on the unit.
    If it has an open connection and doesn't supply ground at any setting, check the
    Light blue/orange stripe wire. It comes from the hvac system and is the wire that tells the module how much ground to give the motor. It should also vary as you change settings. If it does have signal and varies, it is a bad resistor module.
    If It doesn't vary, check the eatc module.
    This is a closed system and doesn't run through the bcm.

  9. #9
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    Quote Originally Posted by fastblackmerc View Post
    Huh? Resistor pack?
    Yes sir the blower motor resistor pack behind the pass head?
    Ford calls it the blower motor speed controller

  10. #10
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    Bwd part number ru1097 without auto temp and part number ru572 with auto temp.

  11. #11
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    Fuse 103 is the 40 amp blower fuse. Engine bay fusebox

  12. #12
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    Or are you guys calling that a BCM.
    Acronyms will get you if you go to ford and order a BCM. You will get a body control module. My apologies if this is the module you guys are referring to as a bcm

  13. #13
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    blower resistor is another term. Greg PM me if you need a scan of the wiring diagram for that circuit

  14. #14
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    I don’t seem to have any ground on the orang/red stripe wire. The fuse is ok.

  15. #15
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    OK. The etac tells the little resistor module how much ground to show the motor. This is what varies speed. High is a straight ground connection and is activated completely separate from the other speeds. It even has its own wire for input from the eatc. If high doesn't work as well as the other speeds, and you have power at the motor, it almost always is not the resistor pack as even when the business end of the resistor pack goes bad, it only effects low and medium speeds. High should still work.

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