air conditioing question

[strat 50]

hey folks!quick question ;does everyones ac come on even when you turn it to "heat" only ?my ac compressor always starts when i turn it to heat and the compressor makes a whining noise at first then quickly goes away.any thoughts ?.......thanks

[Jemdawg]

The AC is supposed to come on when you turn the vents on, whether it is hot air or cold air, it makes no difference. It is only dehumidifying the air. This is common in most new cars, so there's no need to worry.

[marleyfan]

Mine only comes on when I switch it to one of the two front defrost settings. there is no whining sound from mine at all.

A related question. Does anyone know the actual effect on MPG that AC has? Here in the Vancouver area we get lots of rain and cool weather from now til ....well....this time next year. We need the defrost on a lot to keep the windshield clear. Turning off the AC when the defogger is on seems make the defogger ineffective. So I end up driving with the AC on a lot. How much of a negative impact will this have on my MPG cuz right now (after 2 tanks of gas) I'm only getting around 25MPG. That sucks.

[BillStrong]

you MPGs will suck at first. The engine will loosen up and the rings will seat and then boom... you stop using oil and get godd MPG.

You can manually turn the AC off by pushing the button in and turning it off.

simple

[MIdnkight-lude]

here one thing i notices, is that if you turn off the fan with the AC on, and you press the a/c button it doesnt turn on or off. it has to be turn on or off when the fans are running.

[marleyfan]

yYou can manually turn the AC off by pushing the button in and turning it off.

simple

I am aware of this. The problem is that when I do the defogger doesnt work well at all. So It seems like I've always got the AC on. As for the gas mileage. Sure hope to see a big improvement once the break in period is done. The car is way more fun to drive when I'm not focusing on the gas gauge.

[Ever Victorious]

I am aware of this. The problem is that when I do the defogger doesnt work well at all. So It seems like I've always got the AC on. As for the gas mileage. Sure hope to see a big improvement once the break in period is done. The car is way more fun to drive when I'm not focusing on the gas gauge.

Let's clarify two definitions:

Defrosting - the act of heating up glass and/or scraping it to remove frost, ice, or snow from the exterior of the glass.

Defogging - the act of removing condensation or humidity from the inside of glass.

The defroster/defogger on the car relies on the A/C for deFOGGING because the A/C dehumidifies the air. The reason your "defogger" doesn't work when the A/C is off is because you've removed most of the car's ability to remove humidity.

In other words: keep it on if you need to defog.

[motoguy128]

hey folks!quick question ;does everyones ac come on even when you turn it to "heat" only ?my ac compressor always starts when i turn it to heat and the compressor makes a whining noise at first then quickly goes away.any thoughts ?.......thanks

I think you're too used to the old climate controls on domestic cars. The "heat only" that you're refering to is actually the defrost setting. ALL newer cars have the compressor turn on whne you select thsi setting ot better defog/defrost the glass by removing the humidity form the air... this is what causes the fog and frost.

The squeaking you hear is probably comming from the drive belt that drives the compressor. IF you live in a very damp climate, it's not unusual even in a new car ot have the belts squeak. It's mention it to the dealer none the less The belt tensioner could have a problem.

[marleyfan]

Let's clarify two definitions:

Yeah, sorry I used the two terms interchageably. What I meant is defogging. I just find it a shame that I have to reduce my MPG just to defog the windows. My MPG is already crappy as it is.

[michelkenny]

You'll have the same problem with any new-ish car, just not the Versa.

[cnmartin19]

I have a similar problem. My air conditiong turns on every time I turn the vehicle on. According to the manual it should turn on when you have it on defrost but the light will stay off. My AC light turns on every time I turn the car on even when its not on defrost. And its not just that the light is turning in, the compresser is actually on and I have to turn it off every time I start the car. Anyone having the same problem?

[Ever Victorious]

I have a similar problem. My air conditiong turns on every time I turn the vehicle on. According to the manual it should turn on when you have it on defrost but the light will stay off. My AC light turns on every time I turn the car on even when its not on defrost. And its not just that the light is turning in, the compresser is actually on and I have to turn it off every time I start the car. Anyone having the same problem?

Is the air conditioning on when you turn off the car or climate control unit? If so, A/C will automatically revert to the previous state whenever the climate control system is reactivated (by turning it or the car on). So if you park the car and leave the A/C on when you turn off the iginition, A/C will be on when you turn the car back on.

If you are turning OFF the A/C, and have the selector in a non-defrost position, then turn the car back on and the A/C turns ON, then you may have a problem.

[cnmartin19]

I think I do have a problem, because even if I turn off the AC and its not in the defrost position it still turns on whenever the car is turned on, it doesnt seem to matter what position it's at it turns on. The manual also says that when in the defrost postion the AC will be on but the AC light will NOT turn on, which mine also does.

[Ever Victorious]

I think I do have a problem, because even if I turn off the AC and its not in the defrost position it still turns on whenever the car is turned on, it doesnt seem to matter what position it's at it turns on. The manual also says that when in the defrost postion the AC will be on but the AC light will NOT turn on, which mine also does.

No, that part about the light not being on is not true. You can actually turn off A/C during defrost (it will make it far less efficient). Mine also turns on in the defrost position, but the light goes out when I turn it off.

You probably do have a glitch in your car there. You could take it in to your dealership to have it looked at.