Purchase return air filter grilles with washable filters.
You will hear air circulating in the cold air return (or return air grille) when the heater or air conditioner is running.
Nearest to the thermostat.
An air filter resides inside the air return for your car, usually inside the dashboard. This filter should be changed about every 2 years, or sooner if it gets clogged.
Cold air return vents are the ones on the wall
A cold air return is similar to a return air grille, which is needed for air to travel to the furnace to be filtered, heated OR cooled and then recirculated.
The filter on a cold air intake should have a small screw and a clam right were it meets the pipe. (tightening purpose) . The air filter and the pipe are two separate units. If the filter does not have a screw or clam, simply pull and twist off.
There should be appx 15*-20* difference between return and supply air temps measured at the unit (not the registers).
take off the black plastic cover an the air filter should just pull out. but i would go with the cold air intake!!!
Open, that`s where the cold air is.
It is never a good idea to restrict or block a cold air return.
The air filter has no bearing whatsoever on the A/C. However the Cabin Filter may restrict the flow of air to the vents inside the vehicle. Both filters should be replaced every 30,000 miles.