tomus1000

if my a/c compressor is working when the selector is set to defrost?

I have a 2002 Tacoma with A/C. If I use the defrost setting on the selector but do not push the A/C button, is the compressor running? I thought I could here the clutch engaging and disengaging when at idle.

Since it is supercharged, I am pretty concious of gas mileage. I don't want that compressor running and costing me horsepower and mileage unless I need it.

Cebby

I know mine does not engage with the defrost selected. I must press the button separately to engage it. I know this since my defroster doesn't clear my windows worth a crap until I have the AC compressor on (button pressed). Not sure about the newer models though. How does yours clear the windows without the AC engaged?

Jay

Yes, when you turn the dial to defrost, your a/c will automatically turn on regardless of the position of the A/C button.

This feature started sometime like in early 98' i think. My truck does it too.

Jay

91Runner

I just noticed last night when I was driving home from my girlfriend's house, it was raining a lot and my windows were fogging up, so I turned on the defroster and my a/c kicked in. This is in my 2002 Xterra, so it's not just a Toyota thing.

-Braden

justinh

my 1990 pathfinder se did that as well so its been around for awhile...my 1997 4runner does it...the light comes on...but when i use the split option (defrost and lower vents) the a/c light doesn't come on so i assume that it doesn't kick in the compressor on that mode

HBoss

Yes, a/c comes on w/defrost. The conditioned air will clear your windows/windshield much faster with this feature.

Car manufacturers started implementing this more frequently in either 96' or 97', but it's been around for a long time. It's not a Toyota-specific thing, as Acura, Nissan & the like have done it for quite some time too. More recently, car manufacturers such as Acura have started engaging a/c with it set to defrost or foot/defrost vent mode.

mhawker

The reason the AC kicks on with the defroster is that the AC blows out DRY air. If you can dry the air the fog goes away.

Mike- I'm either right or wrong.

tomus1000

Thanks guys, this is useful information. I used to run my heat in the split defrost mode because I hate it blowing directly in my face. I will no longer do this since it engages the compressor and robs power and gas mileage.

Mohamed

You know it really does good to have it on. Trust me on this from experience, the POC camry we have, because of ill use of the a/c system in the winter time, dried up my seals and broke them upon first use in the summer (the oils in the freon helps lubricate these seals everytime you use it) and now I don't know what needs to be replaced since it has been so long. I tried using a sniffer but came up with nothing or the detector wouldn't detect anything. Something tells me I need my compressor replaced if it's a deep leak, and since you must be registered to handle R-12, I gotta pay someone to do it! Ergh !

TDiddy

Yep, I agree, A/C with defrost has been around for a long time and is seen in many different makes and models of cars. Mohamed, I also agree that it does good for the A/C to be kicked on every once in a while. Alot of manufacturers recommend that for the same reasons you mention.

Hermes

Stupid question, but does your A/C light come on when you select ‘defrost’ or mix of defrost/floor option?

I could have sworn my A/C light used to come on when I put it to defrost. But it doesn't seem to do it now.

I know it is functioning correctly, but wondering if I am imagining that the light came on.

Thanks

CLin9383

mine ONLY comes on when i push it in or it's on defrost ONLY..the floor defrost combination doesnt make my AC light come on

Hermes

This isn't a huge deal, but I was just curious. If I read the owners manual correctly it indicates that one must press the button to activate the A/C. But I'm pretty sure it used to light up automatically for the defrost setting.