defrost is hard to get right

[kshon]

whats the correct way to work my front defrost on my m35,i have tried it with the heat ,with regular air and with the ac. and it only works with the ac but this seems wierd. can anyone help with that thanks

[dvan]

only works with A/C

[qship96]

Always a good idea to read the owners manual while sitting in drivers seat and practice using all controls/features of your car to get the maximum benefit out of all the systems!

[kshon]

thanks dvan,thats seems crazy. that means in the winter i will have to put the ac on to clear my front window....nuts

[dvan]

Yeah well the A/C light will be 'on' but you can still increase the tempature to what you want.

[EniGmA1987]

Ya, just cause the A/C light is on doesnt mean it has to blow cold air.

[kshon]

infiniti dropped the ball on that. defrost should be just that and ac should be just that..kinda wierd and takes some getting use to. and for the guy or gal that said i should have read the manual ...for the defrost come on. in every car that i have owned when you press the defrost it's just that. by the way i don't have the owner manual

[szh]

by the way i don't have the owner manual

You can download a PDF of the owner's manual from http://www.infiniti-techinfo.c...id=57 .

Z

[The00Dustin]

infiniti dropped the ball on that. defrost should be just that and ac should be just that..kinda wierd and takes some getting use to. and for the guy or gal that said i should have read the manual ...for the defrost come on. in every car that i have owned when you press the defrost it's just that. by the way i don't have the owner manual

While it is strange that one should have to have the A/C light on in order to use the "defrost," it is not hard to believe considering the other quirks of all Nissan vehicles (for instance, the window lock button locks the passenger windows to where even the driver can't open/close them). That being said, most cars with air conditioners run the compressor when in defrost mode. This is true whether there is an A/C light or not (remember, some automatic climate control systems have vent option, as opposed to an A/C button, and old mechanical systems had Max A/C and Regular A/C on the slider along with defrost and heat, "defrost" ran the compressor even on those). You may have noticed that I placed quotes around defrost. This is because it should also be noted that in some vehicles that have text instead of pictures, this is more accurately indentified as defog, and this is the purpose of the compressor, to blow dry air against the fog, while defrosting does not necessarily imply the need to defog, frost and fog often go hand in hand; you just happen use the temperature to deal with the frost while the compressor deals with the fog.

[ArbitrageMan]

whats the correct way to work my front defrost on my m35,i have tried it with the heat ,with regular air and with the ac. and it only works with the ac but this seems wierd. can anyone help with that thanks

The a/c solves the problem of condensation by adding very dry air to the cabin.

When the glass windows are at a lower temp than the air in the cabin, as air hits the windows, the air's temperature drops rapidly, its ability to hold water drops, and the water its holding condenses on the windows.

The very dry air the a/c puts out mixes with the air in the cabin and so the air's ability to hold water increases. The water on the windows then evaporates.

This is a more efficient method than the alternative, which is to heat the windshield, which is what you're doing when you put the vents to defrost, turn the a/c OFF, and turn the temp up. That heats the windshield, increasing the temp of the air that touches the windshield, which increases the air's ability to hold water, and so no condensation.

In order for that to work though, your engine needs to be warm, and warming up the windshield takes a minute...or so. Running the a/c has an immediate effect.

[ArbitrageMan]

most cars with air conditioners run the compressor when in defrost mode. This is true whether there is an A/C light or not

This is absolutely true. I would even say that ALL cars now run the a/c compressor when you put the front defrost on. This was true going back to my first car, which was a 1989 pontiac grand am. If you put the slider in defrost, the a/c would come on.

[BigP]

Ditto...My experience as well going back at least 20 years...A/C compressor on when defrosting. If you turn it off you usually just get more fog/condensation.

[WhoDey456]

Good stuff guys! I've been wondering about the same thing

[The00Dustin]

This is absolutely true. I would even say that ALL cars now run the a/c compressor when you put the front defrost on.

I said most because there could still be someone out there with a '66 Chevelle with an A/C and the compressor may well not come on for that function. Regarding all new cars, I would assume so, but does anyone know for sure about all-electric vehicles / hybrids in electric mode / super-inexpensive niche cars (tata nano)?

[mjlyn]

Every car i've ever owned back to an 85 Ford Escort 4 speed has run the compressor on defrost.

[ArbitrageMan]

I said most because there could still be someone out there with a '66 Chevelle with an A/C and the compressor may well not come on for that function. Regarding all new cars, I would assume so, but does anyone know for sure about all-electric vehicles / hybrids in electric mode / super-inexpensive niche cars (tata nano)?

Ill bet it does on the Nano, because the mid and upper versions come with A/C!!

[sergio1987]

Sure, i understand everything...but I had a 03 acura 3.2 cl 2 years ago and it would never fog up...the infiniti that i have fogs up all the time when its raining outside...basically i would drive a litlle and than the windows get fogged up, i turn the defog on, the ac on, it works...however after i turn it off the fog comes up again..like in2 min...is this normal? and by the way, even when the windows are opened, the fog appears...
I even changed the cabin air filter yesterday couse i thought that's the reason, but it is not...
I consider the option that there is an issue with my m35x...does anybody know what might couse such a severe fogging?

[The00Dustin]

Sure, i understand everything...but I had a 03 acura 3.2 cl 2 years ago and it would never fog up...the infiniti that i have fogs up all the time when its raining outside...basically i would drive a litlle and than the windows get fogged up, i turn the defog on, the ac on, it works...however after i turn it off the fog comes up again..like in2 min...is this normal? and by the way, even when the windows are opened, the fog appears...
I even changed the cabin air filter yesterday couse i thought that's the reason, but it is not...
I consider the option that there is an issue with my m35x...does anybody know what might couse such a severe fogging?

I get fogging sometimes, but it usually clears itself up without me hitting the defog button. The difference may be that I don't turn off the A/C button year round. I'm not sure how automatic systems do it, but they often know when to kick on the defogger, of course if you turn off the A/C button, this won't do any good, hence my pointing out that I don't turn it off.

[atlM35]

The ac is used to dry out the air. If you have it on vent without the ac on, the moisture will be brought in and condense on your glass. Heat will also dry out the moisture, but it's not practical in the summer.