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Defrost without A/C mod

Discussion in '1st Gen. Tacomas' started by MowTaco, Dec 2, 2010.

  1. MowTaco

    MowTaco [OP] Well-Known Member

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    Hello TacomaWorld

    I can't remember where I saw someone say this, but I didn't see a write up for it anywhere so I thought I'd make one.

    When you turn your vent selector to defrost, the A/C compressor kicks on to de-humidify the air. Maybe there's no sense to it, but in my mind, it seems dumb to heat the air enough to where it won't freeze up the system, then cool it off with the compressor and de-humidify it, heat it back up again (if the temp control is on "red"), then blow it at your windshield. Kinda seems like wasted energy, and there's not much of that to spare (especially on my 4-banger :cool:)
    So this mod allows warm or cold air to be blown at your windshield without the A/C running (basically just shoots it through the same vents but without de-humidifying it first) Keep in mind that it won't be as effective as with dry air, but it will still work. Also, you can easily still turn on the regular defrost setting if you want more effective defrosting.

    It's super easy and takes maybe 10 minutes.

    First, remove your fan selector knob from the climate control panel. It just pulls straight off if you give it a tug. Be somewhat careful, as there is a metal sleeve that fits inside the knob that holds it snug on the little metal post that controls the selector. It should stay in the knob, mine came out and was difficult to get back on in the right shape to fit.
    Next, use a dremel or something similar (if nothing else, a file will work, but be very slow) grind off this little bump on the knob

    [​IMG]

    It should be slightly recessed into the knob when you're done. you may need to remove it and take more off later if it doesn't work.

    Next, pop the knob back into place. If it worked, you should be able to turn the knob past the defrost setting 1 "notch"

    [​IMG]

    It may take a little extra effort if you didn't take quite enough off. If it won't go, grind more of the bump off.

    That's it! :D Your truck will now blow air through the defrost vents without running the A/C. If you want to defrost with the A/C, just turn the knob back to defrost. Easy! I know... you were expecting something difficult with all that buildup... sorry?

    I suppose this was maybe a little too detailed, but I know I sure appreciate it when write ups are painfully thorough... enough for me to even follow :p

    Anyway, enjoy your increased MPG, power, and clear windshield :)
     
  2. vantaco

    vantaco Well-Known Member

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    are you sure that the AC kicks on when you select defrost?

    have you confirmed this?

    the "AC" selector button doesn't not light up when i turn to defrost....yet i am able to push the button and it will light up

    this leads me to belive that the AC does not turn on when the defrost is select but only when the AC button is pushed...many manf use AC to aid in defrost but generally the AC light will turn on to indicate that AC is being used (and you can turn it off)....this doesn't happen in our trucks
     
  3. 707tothe907

    707tothe907 Superior Member

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    Great write up bud! I'm gonna do it just to try it, can't hurt nothin'.
     
  4. MowTaco

    MowTaco [OP] Well-Known Member

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    I never thought it did either. But i can definitely feel the A/C kick on and drag the idle down a little when I hit defrost. Mine sounds like a diesel when the A/C is on, and you can hear it with defrost on too. I'm not sure why the light doesn't light up... It stays the same whether you hit the button to light up or not.
     
  5. Ridgerunner

    Ridgerunner Well-Known Member

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    Yes it is definately linked to the AC. It won't light the indicator because it is not part of that circuit. IMO that is a neat discovery you got there:) How did you come across it?
     
  6. whippersnapper02

    whippersnapper02 Well-Known Member

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    I like defogging my windows quickly so I'll leave mine stock. Nice work though.
     
  7. ywen

    ywen Well-Known Member

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    yeah toyota intentionally enables the AC when the defroster is running. This is easy to test in the summer time when you feel cold ass air coming out of the windshield vents when the defroster is on.

    Toyota's decision to not put the light on in defrost mode has to do with the fact they didn't want people to be concerned with the AC being on esp during winter.. pushing the AC button while in defrost simply flips the light on/off no effect on the AC.

    Thanks for write up! I didn't know a physical notch was responsible for turning the AC on.. Can you on the control panel what button it was pushing?
     
  8. ywen

    ywen Well-Known Member

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    Hmm I wonder if you can just swap the knobs? Do the other two knobs have the same notch as the fan position knob? Will a knob with the knob work as the fan speed or temp dial?
     
  9. cab4you26

    cab4you26 Well-Known Member

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    I like it! My AC light comes on when the defrost is on, not sure why it doesn't for other people. I usually leave it on def./and the one going to the legs because the AC doesn't come on.. I might have to try this though :)
     
  10. pidro_el_pirata

    pidro_el_pirata Lean Mean MPG Machine (best = 27)

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    This notch is what keeps it from spinning 360* right? Think I want to keep that from happening.
     
  11. Space Wrangler

    Space Wrangler Well-Known Member

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    nope. as far as i know, there is only one more position past the defrost setting. it won't spin 360* if you do this mod.
     
  12. Space Wrangler

    Space Wrangler Well-Known Member

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    you missed the point. ...if you do this mod, the ac will still cycle if the selector is set to defrost. ..you just gain the added flexibilty of being able to turn off the ac if you want by moving the selector one position past the defrost setting.
     
  13. ywen

    ywen Well-Known Member

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    OH! so this mod simply allows one more position after the final defrost setting? and only that final position turns off the AC? so if I have it on feets and defrost, the AC still kicks in?
     
  14. derekp

    derekp giddy up!

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    This was discussed a year or so ago. Many thoughts about the need for A/C are: cooler are is drier, making it easier/faster to clear the humidity from the windshield (think rainy days) and running the compressor in the winter, while defrosting, keeps things lubed (not sure I buy that logic, but it was brought up).

    Something else that was discovered; if you turn directly to the newly unleashed setting, the system might not cycle correctly and you might not get the warm air from the windshield vent (it will stay on the last setting). Some found that they have to cycle to the original defrost setting to allow the system to cycle, then turn to the new setting.

    BTW...I did mine also. I love it and it works fine!
     
  15. cab4you26

    cab4you26 Well-Known Member

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    I just realized mine doesn't have the knob, but instead the arm that goes from left to right. Any ideas on how to switch that, too?
     
  16. EL ROJO

    EL ROJO aka Senor Tacorojo

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    TTORA had the 1st right up I've seen a few years back. It is very easy and a cool mod. The ax kicks on for reasons already stated but also, cuz it needs to be run regularly to keep all internal parts lube up. I love this mod. And yes when you use it go one click or setting at a time so that the system can keep up. If it does get outa sync put it back to off and just turn off the truck and it will be fine.
     
  17. derekp

    derekp giddy up!

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    Try taking off the face to see if the arm is able to slide further. If so, then you can look at options to extend the area as needed.
     
  18. ricktaco

    ricktaco Active Member

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    I think all cars do this. At least every car I've ever had did. While this mod will help heat up the windshield to clear off whatever collects outside, it won't help for the condensation on the inside of the windshield. That's the reason they turn on the A/C. Without it, it wouldn't defog the windshield. I've had that problem with a truck I have that doesn't have an A/C. Defrost doesn't help when the inside is fogged up.
     
  19. Space Wrangler

    Space Wrangler Well-Known Member

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    correct!


    ..but this is also true..


    so, say i have the selector on defrost and feet. ..but i then decide i don't want the ac to cycle, i can quickly move the selctor to the newfound setting and it will keep the compressor from cycling ..but it will still keep blowing air out of the defrost and feet vents.
     
  20. whippersnapper02

    whippersnapper02 Well-Known Member

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    No I didn't miss the point. This mod is useless IMO because when do you use the defrost function other than to defrost the windows?
     
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