A/C Doesn't blow cold anymore

Discussion in 'Interior' started by latvius, May 14, 2017.

  1. latvius

    latvius Member

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    Hi I have a 2005 Tahoe with front and rear a/c (5.3L)
    My a/c is only blowing between 70-80 degrees. I have checked the pressures and at 92 degrees outside they are 235 high side and 50 low side. When the engine is off the pressure is 100 on both sides.
    I have manually moved the hot/cold blend door to make sure it is not an actuator problem.
    I did notice the back air is a little colder than the front (about 5-10 degrees colder) and when I am driving on the highway the air is colder than at idle.
    I have verified the electric fans are running, the Tahoe is normal operating temperature and the compressor is running a constant on.


    I've done a bunch of google searches but since it does not seem to be a leak and the compressor seems to be running fine I did not get any good answers on what it could be.
     
  2. M1Gunner

    M1Gunner Full Access Member

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    Year and model, do you have rear heat or just rear a/c?

    Is it dual auto or dual manual?

    Was the system operating when you checked the blend door and you are positive it was a blend door and not a mode door?

    Are you equipped with a cabin filter so you can access the evaporator?
     
  3. latvius

    latvius Member

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    2005 tahoe, I have rear AC dual auto. I have rear heat as well. I installed heater treater which changes the dual door to a single blend door. So I am pretty familiar with the blend door.
    Funny thing is I drove home today when it was 93 out and the AC blew 60 degrees. I ordered freon, dye, a drier and a new orifice tube thinking I would just change those.
     
  4. M1Gunner

    M1Gunner Full Access Member

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    Well here's the thing if it was working today and constantly blowing 60 then there's enough refrigerant in the system to operate which means the change of state of the refrigerant is there thus meaning the office tube is also doing its job. So changing out those components would be unecessary.

    How long have you had the heater treater? Did it start doing this after you installed the heater treater?

    EDIT: is there a chance that new bigger door that may have got hung up and when you moved it manually it was dislodged?

    Because if your pressures are accurate then it's spot on and it's going to be a mechanical issue causing your concern.
     
  5. latvius

    latvius Member

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    No I have the heater treater for a year or so, maybe longer. The readings on the gauges don't indicate anything out of the norm
     
  6. M1Gunner

    M1Gunner Full Access Member

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    Exactly. Those pressures, if they were constant, are showing proper operation. Sounds like a mechanical issue.
     
  7. latvius

    latvius Member

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    I also pulled the ac fuses to get the system to re-calibrate, didn't seem to make a difference but maybe I did not give it enough time. The other thing I was thinking was having the head unit serviced or replace it an maybe change out the temp sensors. Especially if it starts acting up again.
     
  8. M1Gunner

    M1Gunner Full Access Member

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    You can back probe the temp sensors with a multimeter to check the resistance and compare the readings.
    But I'm still weary of that blend door and its actuator. With that bigger heavier door it may have fouled it up. But it's really hard to say over a forums page...
     
  9. latvius

    latvius Member

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    Maybe it just needed to be reset after the winter. Today is was 60 degrees cold on the way home. So far so good.
     
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  10. M1Gunner

    M1Gunner Full Access Member

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    Awesome, hopefully so!
     

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