Center A/C vents blowing very weak air?

DRIVERMODANIEL

MEMBER
1999 LEXUS RX 300
V6
AUTOMATIC
290,000 MILES

My A/C is cold and blows at a good speed on the highest level at the side vents, but not the main vents in the middle. I just checked if my cabin air filter was clogged and there was no air filter present.

Could the lack of a cabin air filter have caused internal damage or blockage to those vents? Or does a bad blower motor resistor cause only some vents to blow weak and the rest good?

Ps. Recently bought the car, has 295,000.

1 Reply

JACOBANDNICKOLAS

MECHANIC
109,747 POSTS

Hi,

I don't believe not having the cabin air filter would cause this and no to the resister. The blower motor resistor is responsible for fan speed and not direction.

The item that is responsible for the airflow direction is called an air outlet servomotor. It is better known as a mode door actuator.

I attached directions below explaining how to test it and the circuit. Take a look through them and let me know if you are comfortable performing the tests. Also, when you have the servomotor removed, inspect the ductwork77
to make sure nothing is disconnected or damaged.

Take care,

Joe

See pics below.

Images (Click to make bigger)