A/C on with defrost

5th Tacoma this one is a 2017. I have modified all the previous ones so the A\C compressor does not come on when in Defrost mode and I could press the A\C button if needed. In other words, I do not want the A\C compressor to come on automatically when in Defrost mode.

How do I make this change?

 

Ok. What are you asking? Or are you just making a statement?

 

...that's the whole point though? Fogged windows are the result of too much humidity. The A/C compressor dehumidifies. Without it, all you're doing is heating the windows such that water in the air won't condense to them. With the A/C compressor you're removing humidity as well, solving the root cause of the problem.

 

95% of the time the A\C compressor does not need to be on for Defrost to work. Having the A\C compressor on when it is not needed affects the mpg. This is a simple modification to get better mpg.

 

That annoys me too. Not so much that it could affect MPG but that you can’t override it.

 

Not if you are using defrost to help with snow and ice. Even with the temp setting on hot, the AC compressor will still be on in defrost mode on a lot of cars.

 

I own a 2017 Tacoma. The air conditioner automatically comes on when I turn on the defroster. I do not like this.
I've owned 4 other Tacomas and was able to alter or override the A/C during defroster setting.
Is it possible to alter this in my 2017 model?
Thank you.

 

+1 I'd like to have full control. Our previous cars let us do that. During the winter, I need a bit more airflow but not a/c to keep my windshield happy.

It is also a bit crazy that if you go full left on the temp control by accident, both A/C and recirc will turn on. Then, I'm poking at buttons to turn it all off.

 

It's what it is designed to do. Most all vehicles do it. It is necessary! I seriously doubt you can see significant MPG changes by ocassionally using the defroster.

What js312 said.

G.

 

It's still beneficial, that's why it's designed that way. Humans exhale very humid air, so you'll cause the humidity in a small space like a truck cab to rise rapidly. In turn, that'll cause condensation on the windows. The A/C compressor helps to prevent that.

 

OK. Everyone look at my first post. I asked how to fix this. I am not interested in anyone's opinion. If you don't know how to fix this, please don't post anything.

 

edit - I see the edit you made now.

 

That was rude.

























































































































I'm almost positive I turned mine off with carista or somewhere in the vehicle settings from the head unit.
Otherwise dealer would be able to with tech stream. Dunno where I did it for mine but remember it was one of the first things I did when I got it.

 

I understand that. I just don't want the A/C on everytime I want the defrost on. When I need to get the fog off my windshield then yes, A/C on is good. When I just need to keep my wipers from freezing to the windshield, then no I don't want it on. I realize it doesn't hurt anything, I'm just controlling like that

 

I don't know about the 2017's. But I haven't owned a vehicle in YEARS that automatically turned the AC on when the defrost was on. I have 3 vehicles in the driveway now, an 07 Tacoma, an 09 Honda, and a 14 F-150. All of them require me to manually turn on the AC if I want to dehumidify. I can run the defrost without the AC, but almost never do. Personally I wish the AC would come on automatically like it did years ago.

Either way this is a huge non-issue.

You might see .1 or .2 difference in MPG's. You're way over thinking this.

 

I turned mine of in settings in head unit.

 

Sorry, but I just wanted to check. If you enable / disable this setting, the a/c will not come on if you move the vent knob to the last three defrost settings?

If so, High5! I will dig in an find this.

 

Just curious (and yes, I'm ignoring your request by posting this) how much gas does the ac really use? 1/2 a mpg? 1/4 mpg? Just seems like a lot of work for a negligible amount improvement.

 

In some enviroments I could see the AC having little effect for defrost being on or off.
No mods other than putting it on foot vent and defrost? Crack a window and your defrosted. Boom.

Also trying holding AC for a few seconds toggling it on/off?

 

Cracking a window does work well, but in the winter when you just want heat. . .

That is one of the problems this automatic A/C issue. It doesn't light the A/C button. Holding it down would be difficult to tell if it turned off.