Fuel Economy

[TinyGiant]

it just dawned on me..

when the mpg started going south was when the weather started getting colder.. and i had to run the Defroster for the front windshield alot.. from what i was reading earlier the defroster runs the AC too... thats probably more likely the cause.. whenever i have the heat on its always on the defrost/footwell setting...

[Revsson]

Originally Posted by TinyGiant

it just dawned on me..

when the mpg started going south was when the weather started getting colder.. and i had to run the Defroster for the front windshield alot.. from what i was reading earlier the defroster runs the AC too... thats probably more likely the cause.. whenever i have the heat on its always on the defrost/footwell setting...

In my 2009 owner's manual, page 178 states that:
"If A/C is not pressed, the system will blow ambient temperature air or
heated air."
And then later on page 183, it states:
"When the outside air temperature approaches 32 F (0 C)
The air conditioning system may not operate even when A/C is pressed."

Perhaps that has changed from the 2007 or 2008 model year, as my buddy
who has a 2007 said that he thought the A/C came on automatically when
he moved the selector to the feet and windshield defroster setting.

Is that a definitive answer or not.

I have heard that other makes of cars use the A/C when in defrost, but who knows?