HVAC Control Module

Discussion in 'Chevy Silverado Forum (GMC Sierra)' started by BowTieFan1, Mar 18, 2012.

  1. BowTieFan1

    BowTieFan1 Member

    On my 2004 Silverado, the lights blew out on the HVAC Control Module. The lights were for the temperature slide controls.
    I removed the module from the dash and took the back cover off, but I do not see any bulbs in there.
    I`m thinking the bulbs are not replaceable, and I have to replace the entire module.
    Anyone have this problem? What did you do?
  2. Dana W

    Dana W Rockstar 3 Years 500 Posts

    The light may be fiberoptic. Do you have a piece of clear plastic on or in the back of the control module? The bulb may be hiding either somewhere in the clear plastic or in the surrounding structure it was sitting in. I found this sort of stuff in car dashs as far back as the eighties.
  3. jlawsonz

    jlawsonz New Member

    My 2005 GMC Sierra lights are on the blink as well. I opened it up just yesterday to check the connections, sometimes they work after hitting a bump.
    There is 1 light on the outside of each slider, they are small 1/16" incandescent lights that stand proud of the circuit board. For the speed and placement rotary knobs, there are 3 or 4 standing lights with blue covers surrounding the knobs, they are more like 1/8" incandescent bulbs.
    There is some fiber-optic like characteristics to get the knobs to light, but I would not call it fiber-optic, but it's more than just backlighting since there is a semi-transparent light allowing film over it for cosmetics.
    I've not yet replaced mine since I'm looking for a source for the bulbs. Radio Crap's Grain of wheat bulbs only last a year or less, don't use those. I did notice that JCWhitney carries the conroller for $138 to $150, depending on if you have rear defrost. I'm planning to replace my whole unit if I can't find the right bulbs. Better price than the stealer at $279 to $380.

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