GMC 2005 T-Series Owner's Manual page 264

Mirrors and Sun Visors Check
Check that friction joints hold mirrors and sun visors
in place.
Seat Adjuster Check
When adjusting a manual seat, be sure seat adjusters
latch by attempting to move the seat after latching.
Lamps Check
Check panel lighting, warning lights, indicator lights and
interior lamps. On the outside, check: license plate
lamps, sidemarker lamps, reflectors or lights on outside
mirrors, headlamps, parking lamps, identification and
clearance lamps, taillamps, brake lamps, turn signals,
backup lamps and hazard warning flashers. Have
headlamp aim checked at once if beams seem
improperly aimed.
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Glass, Mirrors, Lamps and/or
Reflectors Condition Check
Look for broken, scratched, dirty or damaged glass,
mirrors, lamps or reflectors that could reduce the view
or visibility or cause injury. Replace, clean or repair
promptly.
Door Latches Check
Check that doors close, latch and lock tightly. Check for
broken, damaged or missing parts that might prevent
tight latching.
Cab Latches Check
Check that the cab closes firmly. Check for broken,
damaged, loose or missing parts that might prevent tight
latching.
Fluid Leaks Check
Check for fuel, coolant, oil or other fluid leaks by looking
at the surface beneath the vehicle after it has been
parked for awhile.