How to Disable Electrical System

Disabling Procedures

Today, "rip and tear" techniques to gain entry are less effective and potentially dangerous. Access is often much easier than it appears. A more appropriate adage is "try before you pry."

Avoid cutting the vehicle until all of the electrical systems have been deactivated and isolated. Cutting into the areas of the vehicle prior to disconnecting and isolating the electrical energy sources may cause an electrical arc and/or potential injury.

Response Guidelines
First responders should practice safety procedures and caution when approaching or working with the Silverado or Sierra Hybrid Truck during emergency situations. Approach the scene slowly in order to fully develop a mental picture and check for hazards.




Stabilize the scene by addressing the hazards. Secure the vehicle prior to vehicle entry. Ensure that:

- The transmission is in park or neutral

- The parking brake is applied

- The ignition is off

- The key is removed

- And the wheels are chocked (blocked) in some way so that there is no other means by which the vehicle can become mobile.

Neutralize the 120 VAC Outlets




- If the 120 VAC APO indicator is ON, depress the APO button momentarily
- Turn off the engine.

- Remove the key.




42-Volt System
To neutralize the batteries in the ESB, use the service disconnect switch (SDS) located behind a marked removable cover on the right end of the ESB. No tools are needed to remove the cover. Do NOT cut the battery cables, because the higher voltage system has higher arc energy.




CAUTIONS
- Be sure both the 12-volt and 42-volt sources are disconnected before beginning extrication and/or rescue procedures.
- Reduce the risk of personal injury from electrical shock, burn, and damage to any electrical components by always disconnecting 12 and 42-colt system batteries when performing service procedures under the vehicle hood, within or around energy storage box, and/or related to hybrid vehicle systems.




Disconnects 42-volt battery from vehicle electrical system:

- Operates by turning key

- Switch ON = Vertical

- Switch OFF = Horizontal




12-Volt System
Neutralizing (de-energizing) the supplemental impact restraint system (i.e. airbags) in a 12-volt vehicle requires disconnecting the negative battery cable before disconnecting the positive battery cable.

The 42-volt system must be disconnected to fully neutralize the supplemental impact restraint system.