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ANOTHER A/C Question...

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by nvrenuf, Aug 5, 2004.

  1. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    Ok, inspite of the fact I live in an oven I am an HVAC idiot. /forums/images/graemlins/doah.gif Any advice you guys can give with the following problems would be greatly appreciated. /forums/images/graemlins/1zhelp.gif

    Problem 1) It seems like the A/C doesn't blow as hard as it should through the dash vents, I've noticed that in addition to the dash vents a lower center vent directly over (and pointing at) the tranny hump is blowing cold air pretty strong - is this correct? While I've never checked before I always assumed this was a heater only vent. I'm wondering if a damper door is open that shouldn't be causing the upper vents to see reduced air flow.

    Problem 2) At idle and in gear there seems to be a lot of outside odors (exhaust, etc) and humidity coming from the A/C. Lately it also seems like it's not as cold as it previously was, could this also be a damper door open at the wrong time?

    Could problems 1 and 2 be related?

    FYI - I am keeping the A/C on "MAX" and fan speed on "HI" all the time.

    TIA!!
     
  2. pauly383

    pauly383 Daddy383 Staff Member Moderator

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    When A/C is set on Bi-Level air is supposed to also come out on the floor . Perhaps something isn't opening and closing properly .

    For the best airflow make sure to remove cover from firewall ( I opened enough to get brush in ) and clean off your evaporator .

    As to the smells , reseal the airbox on the firewall . Max recirculates inside cab air , shouldn't have too much outside smell at all /forums/images/graemlins/k5.gif
     
  3. 88sub4x4

    88sub4x4 1/2 ton status

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    Check the lever on the mode door. It is a little white plastic thing on the door that the rod from the actuator attaches to. Mine was broken and I went to the junkyard and the first three trucks I took apart were broken also. You have to remove the glove box and the panel on the ac housing to get at the door. I wish I could be more specific, but I did this about two years ago so it's a little vague in my mind.
     
  4. 1-ton

    1-ton 1/2 ton status Premium Member

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    I think you need to dig into the "never never" regions of your truck that most people never go, and make sure all your vent ducting is correctly hooked up. Also, make sure any ducting hose is not deteriorated from age. This is the most likely reason for not getting efficient airflow from the blower motor. Check that your evaporator door (that is the big door the HVAC control panel lever cable is connected too) is connected properly and adjusted to close completely and open properly. Another problem with the evaporator doors is that the foam seal around them becomes deteriorated over time, and lets in fumes from the engine compartment, or will not allow all the cool air from the evaporator to enter the cab of the truck. Also, check to make sure you have an inline heater control valve spliced into your heater hoses. If your truck has hot coolant going to the heater core all the time, this will kill some of the cooling effect that the evaporator provides to the truck.
     
  5. daleearnhardt01

    daleearnhardt01 1/2 ton status

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    [ QUOTE ]
    Check the lever on the mode door. It is a little white plastic thing on the door that the rod from the actuator attaches to. Mine was broken and I went to the junkyard and the first three trucks I took apart were broken also. You have to remove the glove box and the panel on the ac housing to get at the door. I wish I could be more specific, but I did this about two years ago so it's a little vague in my mind.

    [/ QUOTE ]

    Do a search for this topic, CanmoreK5 did a good writeup on how to fix it. I fixed it and its pretty easy. The part is like $0.97 at the dealer.
     
  6. 88sub4x4

    88sub4x4 1/2 ton status

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    Man, I wish I knew about this website then. I figured out alot of these common problems myself and then I find all the advice I need here afterwards. Oh well, I still have lots to learn /forums/images/graemlins/thumb.gif
     
  7. nvrenuf

    nvrenuf NONE shall pass! Premium Member

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    Thanks for all the advice guys, looks like I'm going tunneling into the dash this weekend. /forums/images/graemlins/grin.gif
     

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