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Heater blower problem

Discussion in 'Chevy Trucks' started by Greenery, Dec 10, 2009.

  1. Greenery

    Greenery 2000 Club Member
    Messages: 2,438

    Hey guys, I have a 01 2500 HD and last night while the heater was set on high I tried turning it down and it was stuck on high. Then a little later o still had the selector on high and suddenly it completely turned off. So o turned the truck off and went and shoveled a little bit and when I came back it worked normal again. Now today it's stuck on high again. Any suggestions?
  2. Greenery

    Greenery 2000 Club Member
    Messages: 2,438

    Ok the auto parts guy said it's the blower motor resistor. Does that ssound right I was thinking the switch.
  3. 06Sierra

    06Sierra PlowSite.com Addict
    from Maine
    Messages: 1,329

    Pull the control unit out and check the plugs. I had a 98 that had issues similar to that and one of the plugs was melted.
  4. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Correct, it needs a new blower resistor. While you're in there also check the connector plug when you disconnect it as they have a habit of melting the plug too. You can buy them as replacement pigtails and splice them in, no need to replace the entire harness.
  5. Greenery

    Greenery 2000 Club Member
    Messages: 2,438

    Sweet thanks b&b I was hoping you'd chime in. Thanks to you also 06 Sierra.
  6. Q101ATFD

    Q101ATFD Senior Member
    Messages: 277

    While we're on topic, BB, can you give your thoughts on the manual controls... The drivers side goes randomly from all hot to all cold, and a little in between sometimes, but the control pretty much does not work. The passenger side temp control works and responds fine. I know there's a TSB out on the actuator, but I'm not really hearing the tell-tale clicking noise, or getting any DTC... Temp sensor? Replace entire control unit? TSB applies?
    Last edited: Dec 10, 2009
  7. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    The TSB your probably thinking of also address's loss of actuator control due to an over travel condition of the actuator. Once the actuator over travels the HVAC module loses track of it and can't move or hold it to a specific user commanded position since it doesn't even know where it is to begin with, thus causing the temp swings that you're finding as the HVAC module searches for where the actuator is in it's travel. The system is actually designed to self calibrate every time you turn the key to the run position but often times if the actuator is way too far from it's "expected" location the HVAC module never finds the correct position it's actually in.

    The next time you find it's varying from the command position turn the truck off and disconnect the battery for at least 10 minutes. Then reconnect the battery and start the truck (make sure everything electrical is turned off including the blower motor and dome lamps) and let it idle for about a minute. Then turn the HVAC on and adjust the temp to your liking. If the temp commaneds then hold even for a while the repair procedure outlined in the TSB should fix it.

    And also you don't have to have the clicking noise or any found body codes for the same TSB to apply. Loss of temp control is the #1 complaint for it, no codes or clicking sounds need to apply for it to be the fix. but a broken blend door will also cause it but the battery disconnect info I provided will rule that out if it works correctly afterwards.