defrost setting

[sunny88]

I own a 2007 versa hatchback...and i just have a question about the defrost setting. When i turn my vent selector to the defrost setting, the A/C automatically turns on, and that works perfectly fine on my car, butwhen i turn vent selector to the different positions other then defrost the light on AC button is still on and as i know the AC should automatically turned off if i put the vent selector to different position.Is that normal? like do i have to turn the AC off manually whenever i select the vent selector to different position other then the defroster setting?and you know how air recirculation lever should be on the leftwhen i use heater...but i forgot to move that lever to the left and left it on to the right side... does that make a big damage to my car?

[Ever Victorious]

First of all, welcome to NICO!

To answer your questions:

1) It is normal for your A/C to turn on when you move to the defrost position. It is also normal for it to REMAIN on when you move it back to another position.

2) The lever should be to the left only when you are trying to bring fresh air into the car. Whenever the A/C is on (for either cooling or defrosting), the lever should be to the RIGHT (recirculate). Having the lever in the wrong position will not hurt the car, it just makes the climate controls less efficient when you use it in the wrong position.

[BBISHOPPCM]

This, believe it or not, is an improvement from the original design! On previous Missan products, once the defrost is selected, the A/C could only be turned off if the blower is turned off (but would turn back on if the blower is turned on regardless of vent selection). To reset this, you had to literally shut down the vehicle.

[Rockhound]

2) The lever should be to the left only when you are trying to bring fresh air into the car. Whenever the A/C is on (for either cooling or defrosting), the lever should be to the RIGHT (recirculate). Having the lever in the wrong position will not hurt the car, it just makes the climate controls less efficient when you use it in the wrong position.

I thought it was recommended to Defrost with the air selector on FRESH, not RECIRC.

[motoguy128]

I thought it was recommended to Defrost with the air selector on FRESH, not RECIRC.

This is correct. Although in more extreme conditions, you have to decided if warmer air is more improtant that lower humidity. In sub freezing weather when the engine is cold, it's a tough call. I often start at recirculate and rely on the load from the rear defroster and blower fan to load the engine to help it warm up faster while I scrape the ice or snow off the car.

[johnfeaver]

This, believe it or not, is an improvement from the original design! On previous Missan products, once the defrost is selected, the A/C could only be turned off if the blower is turned off (but would turn back on if the blower is turned on regardless of vent selection). To reset this, you had to literally shut down the vehicle.

On my 2003 Altima, I have this behavior. Is there no software/firmware fix for this "feature"? It tends to defeat the efficiency of my 4-cylinders...

[matttail]

Does anyone know what the actual vent configuration is on these cars? I'm wondering if the car can actually blow properly if you recurclate the air when on the windshield. Are there actaully sperate return and blow vents, or when you put it on this settig is most of the air returning before it ever enters the cabin?

[kc5f]

There's an air flow diagram on page MTC-23 of the Service Manual in the Air Conditioner section. There's also a section on the Intake Door on page MTC-69 that shows the door being on the driver's side below the dash and behind the "instrument lower finisher" panel, separate from the ducts.