GMC Sierra Owners Manual
Add-On Electrical Equipment
Notice: Do not add anything electrical to the vehicle unless you check with your dealer first.
Some electrical equipment can damage the vehicle and the damage would not be covered by the vehicle's warranty. Some add-on electrical equipment can keep other components from working as they should.
Add-on equipment can drain the vehicle's 12-volt battery, even if the vehicle is not operating.
The vehicle has an airbag system.
Before attempting to add anything electrical to the vehicle, see Servicing the Airbag-Equipped Vehicle on page 3‑40 and Adding Equipment to the Airbag-Equipped Vehicle on page 3‑40.