Huh, that pic had a red arrow on my laptop, but it doesn't show here on the work pc. What year is that fit? The aux looks different, in a different place. Is an '09 the same proceedure?

Dan

 

That's an '09 in the pic. I did mine from the pass side.

All you have to do is pry the square plastic cover off that's under the climate controls. You'll want to pull the back of it down. The front hinges and then 2 tabs slide out. There is a long white plug. It's the plug closest to the driver's side under the cover. Pry it out. No more A/C on with the defrost but you can turn it on if you need it.

If it's real damp you will need to run the A/C. If it's just fogging from the glass being cold you can run the defrost without.

Took me about a minute to unplug this "feature". Can't wait to use the defrost to heat up my windshield in the morning without running the A/C.

 

Even my '95 cougar had the ac compressor come on with the defroster. Why is this standard? Seems weird to me. Why involve the the compressor at all? Every car seems to be this way.

Thank you very much for all the details about the mod. I just may do it.

Dan

 

There are two reasons why the a/c comes on with the windshield defroster setting, one its to remove humidy, and it helps the windshield clear alot faster. Two its not good for the a/c compressor to go months on end without being turned on even momentarily (it shortens compressor life).

My 91 accord turns on the a/c compressor when you use the rear defroster, but not for the window defrost.

 

The Rain-X anti fog left nasty swirl-shaped patterns all over the inside of the windshield when I last used it. I buffed it for what seemed like forever and still, at night I'd see the swirl marks that it left whenever I came upon a street light.

I use mine regularly during Skunk Season... and to warm the car during the sub zero weeks that we get here every winter.

I'd say you have wiring issues...

... or have the buttons swapped for Front & Rear Defrosters

~SB

 

EXACTLY. This is just what happened to me the last time I tried that kinda stuff- many years ago. And that's why I won't use that type of product any longer.

Dan

 

I say go for it. I did it and I now have full control of the AC with the on-dash button. I can choose to have the fan blowing on the windshield without the AC when I want that.

 

Was soo nice today to get in the car and run the defrost to heat up the glass without the air. Who wants to run the a/c on a 50 degree morning?

I think manufacturers do this because a lot of people don't know to run the a/c to clear the glass if it's real damp or raining. Most of the geman cars I've had didn't have this feature.

 

Hold on though- if you have the ac button off, the ac isn't technically on correct? I don't see the ac button light up green if it's disengaged and I turn on defrost. I know the compressor kicks on, but a simple adjustment of the temp control can adjust the full temperature range for the defrost. You're not stuck with cold air, regardless. It seems to be a matter of living with the compressor coming on, or doing the mod to take it out of the equasion- unless I'm missing something.

Dan

 

The AC is on when you select the defrost setting of the fan control. The AC switch is off and the light is off but the AC is on. Temperature setting works regardless of the AC being on or not.

The mod allows you to keep the AC off until you actually press the AC button.

 

I don't have the identical fogging problem but I posted this solution that might work for this also. I tested it all last winter and also a few times this summer during cold rain. Worked very well for both.

https://www.fitfreak.net/forums/cana...defroster.html

 

Are you saying the defroster is insufficient to keep the windshield clear in your climate, or you don't like the idea of running the A/C with defrost/defog?

Unless I'm mistaken, the A/C compressor will not run near or below freezing as this will damage it. I think it stops at temps below 45F. Even if you tried to run the A/C by depressing the A/C button it won't engage.

Edit: Some reading confirms this: car A/C won't function below approximately 45F (7C) as the evaporator would freeze up and result in damage to components. The compressor is disabled by sensing the temp of the evaporator. Any mod to avoid running the A/C below 45F is unnecessary. I think the folks in this thread are annoyed with the A/C coming on at temps in the 50's and 60's when they select defog. I'm not sure I understand this sentiment as this is the best way to defog their glass...

Above 45F the A/C will help remove humidity to perform the defog function (especially for those that insist on leaving it in recirculate). At -27C (-16F brrrrr) there is no humidity to speak of after the air is warmed so long as you're bringing in outside air.

 

Steve, what you're saying is what I was always told. IIRC, however, when this was discussed last winter, I tested the theory empirically. The compressor appears to cycle, even at low temps.
Moon

 

I can confirm that. I know that it does in fact cycle at below freezing and the air is cooler and dryer than without the AC on. I remember this because, after I did the mod, I was noticing that the car was warmer and more comfortable on those cold days last winter.

 

Thanks for the feedback! I guess if the evaporator coil is after the heater core the A/C cycling in sub freezing ambient temps would be possible. I lived in Ontario for 5 years, so I'm not unfamiliar with days of sub-freezing temps. Here in GA it may be difficult to recreate though.

 

Base on 2009 Honda FIT user manual page 110.

Dehumidify the Interior

Air conditioning, as it cools, removes moisture from the air. When used in combination with the heater, it makes the interior warm and dry and can prevent the windows from fogging up.
1. Turn the fan on.
2. If the A/C is off, turn it on (if equipped).
3. Select bi-level and fresh air .
Adjust the temperature to your preference. This setting is suitable for all driving conditions whenever the outside temperature is above 32°F (0°C).

To Defog and Defrost

To remove fog from the inside of the windows:
1. Set the fan to the desired speed or high for faster defrosting.
2. Select FRESH AIR by sliding the FRESH AIR/RECIRCULATION LEVER.
3. Select windshiled (Air flows from the defroster vents at the base of the windshield ). The system automatically turns on the A/C (if equipped). The A/C indicator will not come on if it was previously off.
4. Adjust the temperature so the airflow feels warm.
5. Select rear defogger to help clear the rear window.
6. To increase airflow to the windshield, close the corner vents.

It works for me.

 

I have the owners manual for the 91 accord, and it says in it, that the compressor will kick on when you use the rear defroster, and that you should cycle the compressor once a month whether you use the rear defroster, a/c or not.

 

Most cars, especially new cars, have multiple polymers that outgas volatile components, creating a cloudy film on the inside surfaces of the glass. This film exacerbates fogging, and can be difficult to remove; in my experience, the only solution is multiple cleanings with fresh paper towels for each pass. After a few months, it will build up again. My 2003 Subaru still does this; it took four cleanings this week to get rid of the film on the windshield. Some cars are worse than others.

 

Selden, I think you hot the nail on the head. This seems to be my experience with my Fit. I'm the OP for this thread and shortly after I complained I just cleaned the damn thing. Fog wasn't an issue any more for quite a while but now it's starting again. What you mention seems like it could be a contributer. I don't smoke in there so I couldn't imagine what the heck was causing it to get dirty enough to cause fogging. I just figured it was all the more air tight compared to my old clunker. It seems just braking my back and cleaning the sucker takes care of the problem for a quite a while. As for the AC mod on defrost, I'm not compelled to do it. I just don't have the defrost on long enough to care- now that I just clean the thing- DUH. It's a quick in/out and the windshield is clear.

Dan

 

This rings true. I think Honda is putting cheaper plastic in the Fit which may contribute as well.

Running the A/C compressor by default with the defog/defrost is for people like my wife. She insists on running the heat at the warmest setting, usually on recirculate, and then when it gets warm, turning off the fan. Then when the windows fog up she can rely on the defogger working as it's also dehumidifying the air. Drives me frickin nuts. At least she has some other redeeming values. I'm amazed how many cars I see with fogged up windows.

Me I don't care. I tend to keep it on the front vents and if it starts to fog up during rain or heavy breathing I hit the A/C switch and adjust the temperature.