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c/k defroster problems

Discussion in 'Chevy Trucks' started by craigd, Jan 16, 2010.

  1. craigd

    craigd Member
    Messages: 40

    I need some input on this one. I have a 2000 c/k 2500 and i've been having problems with the defrosters for almost 3 years now. Everything works just fine when I leave the house, but within a few hours (usually) the defrosters barely give off any air. The air is blowing just fine...you can hear it in the blower box on the passenger foot area...but very little comes out of the vents. I've had the truck at the dealer 3 times about this and no one seems able to help. Does this sound like a bad actuator? What could cause the position door to get lazy and close? If I turn the temp to cold and move the switch from vent to floor and back to defrost (several times) I can get the defrosters to work again, but only for a short time. I'm thinking about changing the actuator becase it is easily accessible, but I was told by the dealer that I will have less than a 50% chance of fixing my problem. They want to pull the dash and go over everything including the head unit....for $1000. No thanks. Anyone have any advice? I think i've explained all the symptoms. I'm tearing my hair out over this. B and B? Thanks.
     
  2. mcwlandscaping

    mcwlandscaping 2000 Club Member
    Messages: 2,557

    Have you ever tried flushing out your heater core and coolant system? As the motor warms up dirty coolant and a clogged up core could cause issues.
     
  3. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Sounds like the defrost door is moving on its own from either a defective actuator or broken/slipping linkage on it. Highly doubt it's a control issue. Easy way to find out....

    Look under the dash just to the right of the throttle pedal and you'll see the defrost actuator and its linkage. Take a marker and add a few reference marks on it while it's initially in the defrost position. Then after it does it's thing by magically changing on its own look at your reference marks again. Are they now out of alignment on the linkage? The reference marks will identify whats moving when it shouldn't, either the actuator itself or the linkage.
     
  4. craigd

    craigd Member
    Messages: 40

    Thanks. I'll try the reference marks. Now that I know where it is, I can clearly see what it does and how it works. Is there another actuator deeper in the system, near the actual blower? It almost seems like the majority of the air isn't reaching the location of the position actuator. I could be wrong. The reference marks are a good place to start though.
     
  5. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    Yes of course there's more than one actuator and yes it's one of the others that also needs work correctly to allow airflow to the vent/defrost side of the HVAC box in order for the defrost to function. But start with the defrost actuator first since its the easiest to access. :drinkup: