See also:

How to Add Coolant to the Coolant Surge Tank for Gasoline Engines
If the vehicle has a diesel engine, see “Cooling System” in the Duramax Diesel Supplement for the proper coolant fill procedure. WARNING You can be burned if you spill coolant on hot engine part ...

Fuel
For diesel engine vehicles, see “Fuel for Diesel Engines” in the Duramax Diesel Supplement. For Vehicles with gasoline engines, please read this. ...

Auxiliary Roof-Mounted Lamp
If the vehicle has this feature, this button includes wiring provisions for a dealer or a qualified service center to install an auxiliary roof lamp. This button is located on the overhead console. ...