Sierra 3500 4WD V8-6.6L DSL Turbo VIN 2 (2004)
Air Cleaner Restriction Indicator: Description and Operation
AIR CLEANER RESTRICTION INDICATOR
The air cleaner restriction indicator is located on the air cleaner housing.
If the area inside of the clear section is green, no air filter service is required. If the area inside the clear section is orange and Change Air Filter appears,
replace the air filter.