hi- does my 03 sd have a cabin filter?

an air filter for your heat and air conditioning vents?

Ryan

nope!

NOTE: The air distribution system of this vehicle cannot be equipped with a cabin air filter.

There are two sources of air available to the air distribution system:

outside air
recirculated air
Recirculated air is only used when the climate control mode selection is set in the MAX A/C (if equipped), AUTO (if equipped with EATC), and OFF modes.

Air distribution within the vehicle is determined by the function selector switch position (manual systems), or is controlled by the EATC system in the AUTO mode (EATC systems). The air distribution mode on vehicles equipped with EATC may be overridden by the driver if desired. Airflow control doors are used to direct airflow within the air plenum chamber. Vacuum control motors are used to position these airflow control doors.

The air distribution system is designed to provide airflow from the defrost nozzle when no vacuum is applied to any of the vacuum control motors. This is done to prevent a situation where defrost cannot be obtained due to a system vacuum leak.

Air enters the passenger compartment from the:

instrument panel A/C registers (19893).
heater outlet floor duct (18633).
windshield defroster hose nozzle (18490).
side window demisters.
Passenger compartment air is exhausted from the vehicle through open windows or cab air vents.

Component Locations

Item Part Number Description
1 — A/C registers and side window demister
2 18490 Defroster nozzles
3 18471 Plenum chamber
4 19B555 Evaporator core housing

Instrument Panel Registers

There are three A/C registers in the cluster opening finish panel and one A/C register in the instrument panel. All A/C register assemblies can be installed new after removing either the cluster opening finish panel or the instrument panel. New louvers can be installed separately without removing the A/C register assemblies.

I forgot to say to the site!

Stick around and join us all over the place. We're always thrilled to have another member.

Ryan

Yeah, Welcome too!

so you are saying you CAN NOT filter the incoming air? My pete has them on the fresh air intake and on the cab air intake.

You probably could, but the cost would be prohibitive.