Blower motors wont shut off

Discussion in 'GM Electrical Tech' started by skyspy1968, Sep 1, 2013.

  1. skyspy1968

    skyspy1968 New Member

    My 2005 GMC Terrain Z-71 blower motors come on when you start it cold and won't shut off.
    It will kill the battery after it sets.
    I located the relays but don't know where the temp probe is on the vehicle.
    Any help appreciated.
  2. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    Don, if you have a Terrain with auto temp HVAC (you select the temp you want and the unit maintains that temp), your problem is in the motor speed control unit. When the FET transistor fails, the blower motor runs continuously.

    The speed control module should be mounted very close to the blower motor, and most blower motors (although, I don't know about yours) are mounted behind the glove box.
  3. skyspy1968

    skyspy1968 New Member

    Nope I don't have that system.
    I'm hoping its something simple. (Probably Not)
    Taking to dealer Tuesday.
  4. GM Customer Service

    GM Customer Service Epic Member 5+ Years 500 Posts

    We hope your dealer visit goes well on Tuesday, Don. Keep us posted!

    Sarah (Assisting Jennifer)
    GM Customer Care
  5. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

  6. skyspy1968

    skyspy1968 New Member

    Two fried relays,
    Should prove interesting to hear what may have caused it.
    I know where they are located so a dealer trip may not be involved if it happens again.
  7. RayVoy

    RayVoy Epic Member 5+ Years 5000 Posts

    Relays die, the only thing that caused it was bean counters interfering with engineering. A $2.00 relay will last 5 years, a $10 relay would last the life of the vehicle.

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