Can I clip a diode, or juice the computer with 220 volts or something to disable that G.D. AC from coming on when I turn on the defrost? I can't stand that SOB.

It serves a good purpose: dehumidified air does a much better job of defrosting/defogging than regular "fresh" air. Even cold dehumidified air will help prevent window fogging. So you get better defrost results with the A/C coming on. That's why it comes on.

If you really do want to get rid of it, though, I doubt there's an easy fix. It's likely a computer function of the climate control and not something that can be disabled just for defrost. I may be wrong, though.

I disabled this feature when I bought the car. It involves removing the radio, then reaching down by the vent selector switch and unplugging a small wire harness which sends the signal to the ECU to turn on the a/c in the defrost modes. However, as was stated, a/c use does help clear the windows faster.

Why not just use your finger......... that works for me!

Driving Instructor wrote:Why not just use your finger......... that works for me!

Yeah, It's called push the AC button back off.

I want to know how to prevent the A/C from turning on when I go from defrost to front vents.

Thats the one thats truly annoying.

Moghedian wrote:I want to know how to prevent the A/C from turning on when I go from defrost to front vents.

Thats the one thats truly annoying.

Again, use your finger, turn it off.

biggie wrote:Again, use your finger, turn it off.

Im aware of how to solve the situation. Thank you.I was asking if there was a way to prevent this from occurring.

Believe it or not, but this is actually an improvement over the system used in the '01-'04 frontier and xterra (and other models maybe). Once you select "Defrost," even accidentally, it will prevent you from ever shutting off the AC until the ignition is turned off and key removed. That feature drove me INSANE!!

Yes, almost all cars made in recent years have this feature. Some don't even light up the AC switch, just turns it on automatically. Apparently they should have done that on the Versa to keep people from complaining.

I dont think we are on the same page here. Im talking about when Im done using the defrost, and I switch to, say...floor vents, the A/C stays on. In my Kia, when I was done with the defrost, the A/C turned off when I selected another vent setting. I am also well aware of why the A/C comes on to help the defrost, just not why it stays on after im done defrosting.

P.S. Im not saying Spectra is better than Versa. It was simply a comparison.

BBISHOPPCM wrote:Believe it or not, but this is actually an improvement over the system used in the '01-'04 frontier and xterra (and other models maybe). Once you select "Defrost," even accidentally, it will prevent you from ever shutting off the AC until the ignition is turned off and key removed. That feature drove me INSANE!!

That would drive me bonkers.

I understand Moghedian's complaint - if the A/C turns on automatically with a particular vent selection, why not have a 'smart' system that turns it off if the vent selector is returned to the previous setting? Wouldn't be that difficult to control.

But yes, I agree with the others here saying that you need A/C to properly defrost. I used to balk at this 'feature' as an unnecessary nanny, but I've come to accept that during the winter, it's usually beneficial to heat your car with the air dehumidified - not to mention that not running your A/C for several months is detrimental to the longevity of the system.

I know that the newer Infiniti HVAC systems have the A/C on almost constantly, regardless of vent or temperature selection. To bypass this, you use the ECON function. As for my Mazda3, the A/C comes on automatically with the defroster vent selection, much like the Versa, but the A/C light does not illuminate - even though it is obviously running.

I think folks just need to get over it - why would you want the defroster vents on without defrosting anyway?

Moghedian wrote:I dont think we are on the same page here. Im talking about when Im done using the defrost, and I switch to, say...floor vents, the A/C stays on.

Again, push the button off. It's not like it's a gigantic inconvenience to push that button as opposed to screwing with the wiring and possibly voiding the warranty. Just push the button, geez.
Modified by Red Devil at 9:35 PM 1/28/2009

Question: Why are you wanting to disable it? If it's because it sucks gas, just suck it up. You won't even lose 1 mpg off having the a/c come on. It only comes on periodically. And as everyone has said, your windows will take much longer to de-fog or they may not even de-fog at all because you're just blowing humidified air onto them.

Rockhound wrote:why would you want the defroster vents on without defrosting anyway?

Defrost with the air conditioner. Heat with the refrigerator and cool with the Bernz-0-Matic.I think it should be ac on manually if I want it.BTW: Is there any problem with the ac on for 2 seconds then off again 6 to 10 times a day?

boxcarbill wrote:Defrost with the air conditioner. Heat with the refrigerator and cool with the Bernz-0-Matic.I think it should be ac on manually if I want it.BTW: Is there any problem with the ac on for 2 seconds then off again 6 to 10 times a day?

No. It's normal operation. The A/C compressor doesn't operate constantly unless you have it set to the foward vents with a higher fan speed.

ok, so i understand that defoging is better with the ac on, but here in buffalo it can drop from 32 to -10 on some nights, and even just the moisture in the air will ice over the entire car inside and out, i doubt the ac helps that much with that, plus i dont like ac running when i'm first starting my car on such cold days, too jerky for my likeing, id rather let it take alil bit longer than run it

Yeah I agree with the others. If you are reaching down to turn the selector knob anyway how hard is it to push the AC button at the same time?

lordthygod wrote:ok, so i understand that defoging is better with the ac on, but here in buffalo it can drop from 32 to -10 on some nights, and even just the moisture in the air will ice over the entire car inside and out, i doubt the ac helps that much with that, plus i dont like ac running when i'm first starting my car on such cold days, too jerky for my likeing, id rather let it take alil bit longer than run it

then you're probably looking at getting a



or a

I just spent 2 years of my life dealing with this very same stupid issue.

Im 32 and have spent the last 16yrs driving over 500k miles personally with trucks, compacts, hybrids, commercial vehicles and now this stupid 07 Xterra and new breed of cars that try to do auto everything.

Overall i dont mind the car, it does the job and we get along.

But when i bought the car brand new in florida the AC system kept freezing over after 100 mile trips and going into an auto defrost of itself. Something to do with the demisterthingamajigger and the humidity issues in FL

i had to go through a lemon process just to make nissan aware of the problem just so they could bring a guy out after the process to have him mickey mouse the AC core to not run as cold blah blah bs...

nissan basically told me to stick it after that and they were done with me... so this all ended in the spring of 08 when i moved to california and put the issue on the back burner knowing something was still not quite right.

all of a sudden my AC seems to be doing what this thread is talking about. But i wasnt aware that when you turned the dial to the DEFROST or DEFROST/FLOOR mode that the AC would kick on and stay on for X amount of time regardless if you turned the dial back to VENT. The real issue here is that the AC light does not come on in my vehicle when DEFROST is selected and it keeps running after its Turned away.

When you select MAX AC this is obvious and TURNS ON the AC button light like it should. But the light does not turn on for the DEFROST which is #$%&*@# Stupid and is obviously a design flaw. It turns on in my girlfriends altima... so why not mine??

So the gentlemen that is asking how to turn the AC AUTO TIMER off after DEFROST is deselected is asking a valid question.

How do you turn off these things:

1. AC when turned to DEFROST or DEFROST / FLOOR settings. ( i believe this was answered )

2. How do you prevent the AC from staying on after defrost is dialed off?

Call me a child of the old school but nowadays cars are designed to cater to the idiots and old people of the world. If any of you have seen the movie Idiocracy then you know where we are headed. If not go rent it.

The simple solution to this issue is as follows:

NISSANMake it manual.

I want 2 choices for every vent selector except MAX AC1. No AC2. AC

And i want the AC light to reflect accordingly. None of this auto this, and timed that. So 2 years of self diagnosing the car only to have the master tech explain that the AC stays on. I havent found anywhere in the manual that states that the AC stays on after usage is selected off.

Speaking with the Technician tomorrow about issuing a fix for people on this.

IDIOCRACY - http://www.amazon.com/Idiocrac...r=8-1

As far as I can tell my aircon light comes on when I switch to Defrost, if I turn it off it will not switch back on, till I push the button again, or I switch back to Defrost. And if the air con isn't on before I move the switch to defrost it will switch the air con off when I move it from the defrost position. Now you guys would hate Fords then, because the air con runs on every setting except "vent" and "feet" and the only recycled air setting you get it Max A/C. I much like having the choice to set my air recycle as I wish. And don't forget if the ambient air temp is below 47F the compressor wont even cycle. If you're still that worried about it, get a base 1.6 without air con, then you wont have to worry about it ever coming on.

I'll take the setup on the Versa over that on my 09 Outback Sport. On the OBS the AC starts but gives no indication of operation (except that you can hear it and feel the compressor come on and off) and you have no option to shut it off.

I realize that it defogs/defrosts quickly with the AC on, and that's fine when I first get in the car and need to clear the windshield. Once I'm driving though, I'd like to shut it off. All you really need, many times, to keep it clear is just a little moving air over the windshield. You just don't need the AC all the time for this purpose. I can do this on the Versa, I can't on the Subaru and it's one of the very few things about that car that bugs me.

Yes, I have this same problem. When I'm in the defog/defrost modes, the A/C button light is actually OFF, but when I switch to vent it goes ON. I understand why it helps in the defog mode, but I don't understand why it seems to be off then, but on in vent mode . . .

Is this "normal" (still annoying) or is something wrong . . .

(I'm not attuned enough to the sounds of the AC compressor in this car to be able to tell yet when it is ACTUALLY kicking in vs. when the button light goes on . . .)

Brand new 2009 Versa Sedan 1.8S

Mine only comes on when I set it at windshield or windshield/feet vents

I finally decided to attack this problem and was successful in my endeavor.
At 2:46 of this video
https://www.youtube.com/watch?v=8tw8dOsIHrY
is shown 2 wires. A purple one and a beige one. I clipped the purple wire and it disabled the AC on in the defrost windshield positions of the vent selector switch. I would imagine it wouldn't make any difference which wire you clip but the purple one clipped worked. All other vent and AC functions were checked afterward and they all work fine as before the modification.
You don't need to go further than removing the first 2 covers in the video. You also don't need to remove the rotary knobs either but the little square slide knob must come off first.