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2008 2500HD Heat Issues

Discussion in 'Chevy Trucks' started by MattsMowingOH4, Feb 3, 2015.

  1. MattsMowingOH4

    MattsMowingOH4 Member
    Messages: 56

    I have flushed the core. Both hoses are hot, replaced the blend door in the upper dash, and the temp gauge is at 210. Am i missing something as to why i can get little to no heat?!
    :help:
     
  2. skostur79

    skostur79 Member
    from ne ohio
    Messages: 67

    blend door fully closing ?

    auto climate control?
     
  3. rjigto4oje

    rjigto4oje PlowSite.com Addict
    Messages: 1,298

    Sorry to ask this I'm on my phone. Some vehicle's use a cabin air filter it may be full of dirt leaves or ? Hows the air speed if all of what i posted is not the problem. Then like said b4 Blend door isssue
     
  4. MattsMowingOH4

    MattsMowingOH4 Member
    Messages: 56

    I would have to check the cabin filter

    The blend door i replaced moves as it hold but has no effect on the heat. Is there another that i am missing?

    I have a work truck so no auto climate
     
  5. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,005

    You sure that was the temp door you replaced?
     
  6. MattsMowingOH4

    MattsMowingOH4 Member
    Messages: 56

    After a little research I found my truck dosnt have a cabin filter. GM stopped truck cabin filters in 2003
     
  7. skostur79

    skostur79 Member
    from ne ohio
    Messages: 67

    if the hoses are both hot

    and you moved the correct door by hand to full hot

    you have a heater core issue or u moved the wrong door ,,


    u don't have a cabin filter on a 08
     
  8. MattsMowingOH4

    MattsMowingOH4 Member
    Messages: 56

    The actuator motor i replaced was the upper blend door Its kind of behind the radio, upper glove box

    I cannot find anything else to replace other than the thermostat, but my temps are right
     
  9. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,005

    That's the direction door.
     
  10. rjigto4oje

    rjigto4oje PlowSite.com Addict
    Messages: 1,298

    Thanks 4 pointing that out I know they did away with them couldn't remember what year year
     
  11. MattsMowingOH4

    MattsMowingOH4 Member
    Messages: 56

    What part do i need to replace then
     
  12. mjk1968

    mjk1968 Junior Member
    Messages: 2

    The actuator motor that was replaced, was it an original GM part? The reason I ask, I bought a replacement actuator motor for a similar vehicle and came to find out that the motor turned in the opposite direction than what is was suppose to. If you run your temp dial to cool and start getting heat that's your problem. If so, easy fix the motor is 12 VDC and just reversing the two motor leads will get the motor to reverse and now your blend door will work properly.
     
  13. MattsMowingOH4

    MattsMowingOH4 Member
    Messages: 56

    Yes its a factory part

    dug more into the truck the actuator motor for hot/cold moves when switching, and the re-circulate actuator moves when pushing in between those two settings… whats next?

    tried pulling the fuse and resetting the system with no luck there either
     
  14. Rick547

    Rick547 Senior Member
    from Indiana
    Messages: 535

    Did you flush the heater core or the radiator?

    Which two hoses are hot, the heater hoses or radiator hoses?
     
  15. dieselss

    dieselss PlowSite Fanatic
    Messages: 11,005

    It might be hard, but can you actually see the door closing? A few years ago, Gm had some issues with the rod that held the door on. Well late 90s I should say. I'd double Ck that
     
  16. maxwellp

    maxwellp PlowSite.com Addict
    Messages: 1,112

    A heater core can get some what plugged so all the tubes do not carry hot water. This makes the discharge temp low but both hoses will still be hot.
    I just did one in my 01 Dodge that was doing the same thing. 190 degree water and you would freeze, would only have a 70F discharge temp. I now have tons of heat with the new heater core.
    Just info - I do not have any Chevys. Plus your is newer. Does it have a ton of miles?
     
  17. rjigto4oje

    rjigto4oje PlowSite.com Addict
    Messages: 1,298

    I have a few secrets on flushing heater cores. Take the hoses off, get a piece of hose around 1 foot, cap one end of the core off pour clr in the piece of hose that you connected to the otherside of the truck let it sit for a while the clr breaks down. Then i use shop air or water depending on the season to flush the core work most of the time. I also have an old fire extinguisher that can be filled with water i fill it up with hot water get a piece of hose presurise the extinguisher with shop air blast water through it work well hope this helps
     
  18. Mems

    Mems Senior Member
    from Maine
    Messages: 202

    Its the actual heater motor I bet. I just had to replace this and its about $100. It is up under the dash just behind the glove compartment and looks like a big fan filter. pretty easy to replace, a few screws and then just twist it out.

    https://www.youtube.com/watch?v=jrGFY6yqvFM
     
  19. damian

    damian Senior Member
    Messages: 330

    I agree with Maxwellp but I have never had much luck flushing these cores even with heroic measures such as shop air blasts ,vinagar solutions,and other methods. After assuring the blend door is working as it should you may be looking at heater core replacement which is no fun on that truck.
     
  20. K.C.C.

    K.C.C. Junior Member
    Messages: 7

    Just curious, is this with the plow on or all the time? My '08 2500HD wont blow heat with the plow on going down the highway but it's fine while around town or with the plow off.