Rain water leaking through the blower fan housing on passenger side 1999 gmc suburban. Air-water appears to coming in through holes under the wipers suggest a plugged vent hole. Help find?

It sounds like the drain holes in the cowl area might be clogged, causing rainwater to accumulate and leak into the blower fan housing. To address this, check for debris or leaves blocking the drain holes located under the wiper blades. Cleaning these out can help redirect water away from the ventilation system. Additionally, inspect the seals around the windshield and cowl for any potential leaks that may need repair.