Master Electrical Schematic Icons

Icon	Icon Definition
Courtesy of GENERAL MOTORS COMPANY	WARNING: When performing service on or near the SIR components or the SIR wiring, the SIR system must be disabled. Refer to SIR Disabling and Enabling. Failure to observe the correct procedure could cause deployment of the SIR components, personal injury, or unnecessary SIR system repairs.
Courtesy of GENERAL MOTORS COMPANY	SIR Schematics: WARNING: The connector at the Inflatable Restraint Module cannot be disconnected or removed without damage to the module. If the connector is removed from the module, the entire module with harness must be replaced. Power Take-Off (PTO) Schematics: NOTE: The vehicle is shipped with this circuit included in the wiring harness. Utilizing the factory configuration, the PTO will not work without this circuit. It is possible for this circuit to be removed by an upfitter when adding aftermarket switches to the vehicle. Refer to Upfitter Documentation for more information.
Courtesy of GENERAL MOTORS COMPANY	Headlight/Daytime Running Light Schematics: WARNING: The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns: Never open the high intensity discharge system ballast or the arc tube assembly starter. Never probe between the high intensity discharge system ballast output connector and the arc tube assembly. Engine Control Schematics: WARNING: High voltages may occur in Piezo Fuel Injector and control units, Fuel Injectors are usually charged up to 160V, and control unit internal voltage is usually 240V, To prevent personal injury and/or component damage disconnect the battery cable.
Courtesy of GENERAL MOTORS COMPANY	NOTE: Twisted wires provide an effective shield that helps protect sensitive electronic components from electrical interference. In order to prevent electrical interference from degrading the performance of the connected components, you must maintain the proper specification when making any repairs to the twisted wires shown : The wires must be twisted a minimum of 10 turns per 31 cm (12 in) as measured anywhere along the length of the wires. The outside diameter of the twisted wires must not exceed 6.0 mm (0.25 in).
Courtesy of GENERAL MOTORS COMPANY	NOTE: Always perform the High Voltage Disabling procedure prior to servicing any High Voltage component or connection. Personal Protection Equipment (PPE) and proper procedures must be followed. The High Voltage Disabling procedure will perform the following tasks: Identify how to disable high voltage. Identify how to test for the presence of high voltage. Identify condition under which high voltage is always present and personal protection equipment (PPE) and proper procedures must be followed. Before working on any high voltage system, be sure to wear the following Personal Protection Equipment: Safety glasses with appropriate side shields when within 15 meters (50 feet) of the vehicle, either indoors or outdoors. Certified and up-to-date Class "0" Insulation gloves rated at 1000V with leather protectors. - Visually and functionally inspect the gloves before use. - Wear the Insulation gloves with leather protectors at all times when working with the high voltage battery assembly, whether the system is energized or not. Failure to follow the procedures exactly as written may result in serious injury or death.