AC blower motor fan switch

Discussion in 'Electrical Systems' started by 1st and goal, Jul 25, 2017.

  1. 1st and goal

    1st and goal Veteran Member

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    I've recently lost high speed on my interior blower motor. I replaced the fan switch and also replaced the blower motor relay as I understood that to run high speed and the blower motor resistor ran low and medium speeds.
    The air still works, just on low and medium fan speeds. I replaced the blower motor a couple of years ago.
    What else am I missing?
     
  2. Gary S

    Gary S Administrator Lifetime Gold Member

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    You are replacing the wrong parts. High speed runs through a separate wire and a relay. Check that circuit for a bad wire, bad connection, or bad relay.
     
  3. Twisted_Metal

    Twisted_Metal Administrator Staff Member Lifetime Gold Member

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    Check the big pink wire at the relay for power.
     
  4. budro6968

    budro6968 Veteran Member

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    I seem to remember an in line fuse inside a black insulated fuse holder for the high only. The wire is black too.
     
  5. twozs

    twozs Veteran Member

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    on my 73 its red and has a 30 amp fuse . It runs from the horn relay to the plug on the fan relay . It's the only fuse that not in the fuse box on the car .
     
  6. Scott51

    Scott51 Veteran Member

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    Sounds like you're missing a circuit tester, :)

    start by checking the pink wire at the relay like Twisted said. If it's dead work backwards to the battery, (fuse, bad connection etc) if it's live, switch the heater to high and check power is coming out of the relay, if that's not doing anything check the trigger wire from switch to relay and relay ground and so on

    Just think of the wiring as a road going from point A (battery) to point B (blower motor) then it's just a simple process of elimination to find out where it's getting lost
     
  7. 1st and goal

    1st and goal Veteran Member

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    Thanks guys, sorry I forgot to post back in case anyone else has a similar issue.
    It ended up being a melted fuse holder so the relay was not getting any power. Replaced the fuse holder and am good to go.
     

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