AC compressor defrost mod

Discussion in 'DIY Instructables' started by Cotts612, Nov 30, 2013.

  1. Cotts612
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    Cotts612 Active Member

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    I did this on my 04 wrx wagon.

    This mod will allow you to use the windshield defrost and windshield/floor vent selection without your ac compressor running automatically. There are already some posts on Scooby mods about this, but the pictures aren't the greatest and I'm not using a soldering iron to remove any wires.

    http://www.scoobymods.com/showthrea...1262.html?threadid=1262&highlight=a/c+defrost

    NOTE: In some wrx's, the ac light comes on and you can push the button to turn it off. This mod is for the vehicles where pushing the ac button does not turn it off in said vent selections.

    NOTE: It is also recommended to run the ac compressor a few minutes a month to keep the seals lubricated.

    What you need:

    Long Philips head screw driver
    Mini (jewelry) philips
    Needle nose
    Zip tie
    Patients
    45 minutes or so

    I worked from the passenger seat the whole time. Seemed to work out well

    First, open up the cup holder and remove those 2 Philips head screws. Remove cup holder.

    Next, carefully remove the plastic trim around the radio and hvac controls. No need for a screw driver, your fingers should work. It's held in by 4 or 6 plastic tabs. Just work your way around it.

    Now that the trim piece is out of the way, you can start to remove the radio. There are 6 screws (3 on each side). Remove the 6 screws and slowly pull out the unit. Remove the ground wire from the passenger side of the radio. Then pull it out enough so you can remove the antenna wire and the wire harness/clip. There should be enough slack in the wires to pull it out enough. Just pull slowly.
    1385750489944.jpg

    With the radio removed, you can now gain access to the hvac controls. Remove the 4 screws holding it in place. DO NOT try and pull the hvac control unit out. I have no idea how to remove it. I only unscrewed it so I could move it just enough to get to the bottom side of it.

    Here's the culprit: Plastic tab #1 pushes metal tab #2, into a small button that turns on the ac when on defrost or defrost/floor
    IMG_20131129_134349.jpg


    Gently lift up the passenger side of the hvac controls so that you can see the bottom of the micro switch. See that brass colored little screw? Remove that. Be very careful when moving this unit around. Try to not lose the screw, just in case you want to put it back the way it was. Needle nose helped get the little guy out safely.
    1385750942151.jpg

    Here's the micro switch removed from it's mounted spot
    IMG_20131129_134440.jpg

    Next I put a ziptie around one end of the switch so that if it gets pushed by something, it wont reach the little button. There are more ways to do this than a zip tie, but that's all I had to work with. You could also take a soldering iron and remove one of the purple wires. I elected not to do this.
    1385752240311.jpg

    I tucked the micro switch back in, but did not install it back in it's original spot. It hangs down a little, but there is nothing that will touch it. Plenty of room.

    Now your ac compressor will not turn on unless you push the AC button.

    Reinstall opposite of removal.

    Good luck
     
  2. TMF
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    TMF Well-Known Member

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    Cool, I was wondering if there was a way to do this. Thanks for posting!
     
  3. pillboy
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    pillboy Well-Known Member

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    Why?
     
  4. 05CGFozzie
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    05CGFozzie Member

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    I concur, why? The a/c takes the humidity out of the air and that's what helps de-fog/deice the inside of the windows.
     
  5. Cotts612
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    Cotts612 Active Member

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    It's our duty as Subie heads ;)
     
  6. Cotts612
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    Cotts612 Active Member

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    I usually like the heat to be on the windshield and floor settings, and I didn't like the idea of my ac compressor running all winter long. I'll use the ac from time to time, when it's really sloppy out or raining. My windshield didn't fog up at all today in the wet snowy mess. Just turned the heat all the way up and had it on low.
    Keeping the inside of your windshield clean also helps. Dirty windows fog up easier as we all know :)
     
  7. TMF
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    TMF Well-Known Member

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    Yup, this ^ and running the AC when you don't need it causes worse gas mileage and robs power. I also like air circulation, but I don't always want it blowing out the front vents.
     
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  8. Takalak
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    Takalak Member

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    Im finna do this
     
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  9. tangledupinblu
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    tangledupinblu Event Coordinator Staff Member

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    Yes, this applies to our bugeyes! I'm literally sitting at BWW's right now listening to the idol bounce up and down like the AC is on. I may have to do this one also!

    Thanks for doing the write up @Cotts612!!
     
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  10. Cotts612
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    Cotts612 Active Member

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    No problem. I'm super anal about that kind of stuff, and it bugged the crap out of me that the ac would literally be on all winter. First "mod" on my car and one of my first posts here!
     
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  11. pillboy
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    pillboy Well-Known Member

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    Everything I have ever read says it is good for the AC compressor to run regularly to keep the lubricant in the refrigerant moving throughout the system which keeps the seals from hardening and causing a leak. If you are this concerned with fuel mileage a Subaru is not the car for you.
     
  12. retreif
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    retreif Well-Known Member

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    I'm pretty sure even if you do this mod, you'll have the AC on enough times to lube it.
     
  13. Cotts612
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    Cotts612 Active Member

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    It's in the winter when you need to be careful. Easy to forget about it. I turn the ac on a few times a week in the winter for the sole purpose of lubricating the seals.
     
  14. Takalak
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    Takalak Member

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    I may not do this if i owned my car brand new from the lot. But im the third owner and can tell the ac system was somewhat neglected. Such a noticable power loss with it on as well. The mod is cheaper than a new compressor and seems like it can be reinstaled at will. Im still doing it.
     
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