99 Concorde HVAC Question

Discussion in 'Concorde' started by HH, Oct 5, 2005.

  1. HH

    HH Guest

    I have a Concorde 1999............has a electronic display/controls for the
    HVAC.....blower motor rotary/speed switch is part of the underlying control
    All works with exception that fan is on high all the time regardless of
    rotary switch position. I have seen posts that say a common problem is open
    resistor and possibly worn motor wrecking the resistor. These posts all
    refer to the fan only working on high "position". Mine is on high regardless
    of switch position. Even when HVAC switched to off. Resistor? Something
    HH, Oct 5, 2005
  2. HH

    Steve Guest

    I can't say for sure about a 1999 Concorde (second generation) but on
    the first-generation Concordes, the electronic HVAC system doesn't use a
    simple resistor for fan speed control. There is a module under the dash
    near the fan motor that receives the commands from the control head and
    then regulates power to the fan motor (either a linear power amplifier
    or a pulse-width modulator, I never bothered to test and see but its got
    some power transistors on it). When that sucker fails, you get (you
    guessed it) high fan all the time. IIRC, it was order of $50 to replace.
    Steve, Oct 5, 2005
  3. HH

    HH Guest

    Thank You!! That is why I posted like I did. If there was a resistor issue
    it would shut off when hvac off. I could see the small gauge wire on the
    back of the board and knew there had to be something else. I suspected there
    was a motor control down the line. Truth is, it is my neighbors kid next
    door ( car ) and their broke. I told him i would see what I could do. Thanks
    HH, Oct 5, 2005
  4. HH

    philthy Guest

    sounds like the power module for the blower motor is bad if u have the manual
    havc controller then u have a blower resistor but the auto system has a power
    which is a pulse width modulation driver and is more costly to fix
    philthy, Oct 8, 2005
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