A/C on with Defrost

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So I got bored and wanted to disable the A/C from coming on when selected the mixed(floor/windshield) and windshield only modes on the environmental selector. It kind of sucks to have the heat on in the middle of the winter only to have the A/C turn on and waste MPH.
So consider this is an Eco-Friendly mod!
After looking at the schematics I found that the green wire from the D3 connector triggered the A/C amplifier to engage the compressor. There is also a separate trigger wire for the manual A/C switch. Bonus!
Here is how it's done:

Locate the D3 connector on the defroster servo and remove it.


Remove the white retainer and insert a small piece of wire to release the SOLID Green #3 wire. Not the Green with Black stripe.




Fold it back for safe keeping and tape it up to prevent shorting.


Then plug it back into the Servo. Don't forget to re-install the white retainer!!


I've tested this for a few days and the A/C will still turn on with the manual A/C button on the environmental control panel.

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Edit:
There were some questions on how to remove the terminal from the plug (plastic) and I just wanted to clarify for those who have yet to take one part.
After you remove the white retainer, you still need to insert the helper wire, into the inverted 'T' slot below the square slot, to remove the spring loaded clip still holding the terminal to the plug.

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Edit:
Fellow TW member rlg0613 suggested a jewelers screwdriver which I didn't even think of.

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Edit:
I added a diagram to clarify this.

 

Neat mod. It would be nice to be able to bring that green wire out to a dash switch. That would allow the A/C to kick on when it's fogging up due to high humidity in the cabin. I know a lot of times in cold weather the problem is the cold windshield, but there are times (even with the heat on) when the A/C helps. Just my un-scientific opinion.

Bob

 

You still can, have the heat on and the A/C for the dehumidifying.
You just press the A/C button.

 

nice write up, country boy!! this should be stickied, or put in the cheap mods thread!! good job!!!

 

WOOT! I've been waiting for someone to find a way to do this!
+ to rep for being a genius!

 

If anyone wants to recommend this as a Sticky or added to PT's list, feel free to nominate.
I'm just sharing some helpful things I've found.
I'm just to modest to nominate myself!

 

Doh! It was a long day, my brain wasn't in gear...

 

Awesome find. Looks fairly simple to do. I was bummed when toyota first decided to activate A/C when defrost is on. Most defrosters work with heat not a/c. Whats the deal?

 

you get some rep for that one ctryboy! too bad i'm afraid to touch the wiring on my truck.... who wants to do it for me?

 

ndcouch, that is not ignorance (compliment) is your way of doing things, lazy boy, easier for you open your windows and that will defrost even your wettest ideas, that is if you have the pw if not burn baby burn, hot and humid.

 

Dan? is that you?

 

Added to the T.O.C.

 

Ok, so what panel did you find the connector behind, and how does it come loose?

 

The only thing you need to remove is the glove box. Push in on the two limit stops holding it and lift the box off the hinge. The First picture is taken from the passenger seat looking toward the center of the dash through the opening left from removing the glove box.

Edit: Just about forgot... If you still have that pathetic waste of a shock on the glove box, you need to remove that, too!

 

So you are telling me the AC comes on when I select defrost (windshield)?

 

If you have Air Conditioning, yes.
When the environmental selector is set to either Floor/Windshield mix or Windshield only, the A/C compressor is triggered. The inlet air runs through the A/C condenser before it is ran through the heater core and delivered to the system.
The engineering thought process behind this layout is to "dry" the incoming air, reducing the fog buildup on the windshield.
In all justification, this process is sometimes needed on humid days when the windshield is cool and the incoming moisture condenses on the windshield (creating fog). Once the windshield is warm enough, this "Drying" is no longer needed. Unfortunately the system cannot detect this and continues to run the A/C system.

We 'Smarter than the average human' Tacoma owners do not need this.
We will immediately recognize this situation, therefore taking the appropriate corrective action and push the A/C button.
Likewise, when no longer needed, we can opt to de-select the A/C function reducing the drag on the engine and increasing power and fuel economy.

 

Hmmm, I did not know this. Good info. However, I don't see why in the hell I would need this. I live in the driest damn place on the face of the earth. What's humidity?

 

countryboy, that is very interesting, what is the year of your truck? I'm wondering if this is the same for an 08 tacoma? Anybody done this on an 08?

 

I did my '08 Prerunner about a week ago. It's been pretty rainy here and I have had to turn on the A/C only once and for only about 30 seconds. The front and back windows cleared and I went back to Eco-Friendly driving.

No joke - this is a HP boost mod!

 

It whould be the same on all the second generation trucks.