This has bothered me for some time now but I will ask now. Why is it that in Japanese car you need to have the a/c on in order to heat your car so that the windows do not fog up. I also own a American car and I do not need a/c on to use the heater... any help will be awesome! Im just curious. Thanks!!!

 

thats weird, all HVAC systems, foreign and domestic, work using the same principles

 

Have you had an encounters with this? Also which is weird needing a/c on or not needing it on?

 

A lot of them do it without you knowing.....

The whole point of having the A/C on to defrost is it dehumidifies the air.

 

Muffin is on point, this wasent a requirement or wasent commin practice till around like 99 or 00+- . It should be only for defrost you should be able to turn on your heater in other modes and should be just heat.

 

yeah ac is good at removing moisture from air, hence the need for a drain tube from the evaporator. whenever i defog windows i use heat and ac at the same time. newer cars may do it automatically

 

Muffin man is correct, however a little known fact is that on some model cars (Honda in particular) you can disable the AC/defroster combo. The info can usually be found in a legendary book called....wait for it.........the owners manual. Of course no one ever reads that.

 

and GM cars were doing this in the 70's

 

x2!