daiyi3

1) When you have AC off, and car at ON mode(meaning tap the start button twice without putting feet on pedal), do you hear a hissing or vaccuming sound at the behind the central AC vent/audio system?

2) When you have the AC on, and car engine on, turn the AC mode to feet and frontwindow mode, put ur hand on the left or right side of the AC vent (ones beside the window), do you feel AC blowing out?

Those seems really weird to be normal...

daiyi3

oh and i drive a 2009 TL AWD

daiyi3

Tech

Hogan9166

iTrader: (1)

Yes on the side vents. That's intended to defog your side windows.

Don't know about the other.

dirtyo2000

The hissing noise is vaccum in the lines that actually open and closes the blend doors in the car. Since the engine is off there is no vacuum being created and the little that is left in the system is being expelled. The reason you hear it when you hit the button is the electric valve opening allowing the air to the actuator.

A/C doesn't really blow to the floor that cold since it's passing across the heater coil. It will be warmer than the air that comes out the vents since it's stright from the condenser and not crossing the H/C. Whenever you place air to the windshield it comes through the side mirror vents to defog the window.

All air to the front windshield crosses the heater coil to add the moisture to the air. If it was straight off the AC it would create a frost and dew on the windshield. You would have cold air blowing against a hot surface. Main reason when you turn on the defrost without the A/C the window clears then starts the fogging up right above the vents and slowly goes across the windshied.

Anything other than bringing the AC through the vents and you are carrying it across the HE in the car

daiyi3

So im guessing the hissing noise is normal as well?

aIRpeACE

iTrader: (2)

maybe

mightl

Dirtyo2000, are you a service provider for the auto industry? your depth of knowledge really impressed me.