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Heater fan speed question for an older

Discussion in 'Chevy Trucks' started by gd8boltman, Dec 7, 2005.

  1. gd8boltman

    gd8boltman Senior Member
    Messages: 328

    Chevy. One of my trucks has all blower motor speeds except high, when you turn it to high it shuts off, all other speeds work fine, it is an 85' , any ideas, I am sure I am no the only one who has had this issue.


  2. payton

    payton Senior Member
    Messages: 470

    one of 2 things..

    switch.. or motor.

    im gonna guess its the switch.. not making full contact in the high postion.
    might be able to clean it if not im sure you can replace it for a few dollars.

  3. 75gmck25

    75gmck25 Senior Member
    Messages: 119

    If its wired like my '75 GMC, high speed on the blower has its own dedicated fuse and relay. This fuse is not located in the fuse panel.

    The high speed fuse is in a line that runs across the back of the engine compartment, at a level just above the distributor. This line goes from the junction block just above the driver's side valve cover, directly over to the heater blower relay.

    I don't remember the details of how this relay/fuse setup works, since its been a while since I've had to troubleshoot my own. However, I have the wiring diagrams for my '75 and can look it up for you if you need the info.

  4. gd8boltman

    gd8boltman Senior Member
    Messages: 328

    Thanks for the info. I will look into it and let you know, I will check all of the items you mentioned.