RepairPal Certified shops can diagnose and repair your 2000 Chevrolet Tahoe. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
Could be the blower motor. Stop by a shop, they would know right away. Hands-on inspection needed.
Use this link to find a good shop near you.
https://repairpal.com/repair-shops
Alex