See Figures 1 and 2
The Vehicle Identification Number (VIN) plate is mounted on the driver's side of the instrument panel, and is visible through the windshield.
The models covered here include full size C/K trucks including the Tahoe, Blazer, Jimmy, Yukon and Suburban. Starting in 1992 the Blazer was renamed the Blazer/Tahoe and Jimmy the Jimmy/Yukon. The 5th digit on the vehicle identification number is the vehicle line and chassis type: