This is where leaves build up, on both sides of the truck. They come thru the wiper valance slots ('80-86) and between the windshield & its lower trim (all). This valve is more easily accessed by removing the 5.5mm (7/32") screws from the edge of the wheelwell (harder with running boards), but expect a face full of rotten leaves & bugs if you work from below. Lucky owners will find live ants.
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It's easy to remove the evaporator (WITHOUT venting any refrigerant) and wash it out for better airflow, better cooling, and fewer odors.
To keep leaves out of the passenger side (where the HVAC intake is) and force them to the unused driver's-side drain, add screen at the top, just below the wiper valance:
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To keep leaves out of the ventilation system, add screen inside the cowl by removing the wiper valance & working through the rubber plug under the antenna:
See also:
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