Objective: Identifying when and how to use High Voltage shutdown procedures on Tesla Model S
- Tesla Model S has had some changes since the beginning of its production but reliable high voltage shutdown has remained the same.
- In this Tech Tip we will look at the various options that have emerged for high voltage shutdown and their effectiveness for responders. Tesla uses a LOW voltage “cut loop” to isolate power to the battery
Findings: High voltage shutdown for Tesla Model S has been presented in two different ways depending on its model year. One of the methods has proven reliable and another has been found to be difficult to execute.
- Method 1 is the unplugging or “double cutting” the first responder cut loop. The cut loop is located on the passenger side front trunk, near the firewall under a cosmetic cowling cover. Unlike other Tesla models this cut loop can be unplugged if preservation of the wiring harness is desired. When cutting, the Tesla ERG recommends double cutting the cut loop to ensure the memory in the wire does not re-connect the circuit. (See Figure 1)
- Method 2 is offered in only some model years and always in addition to Method 1. In some vehicles a second cut loop is located in the rear drivers side door sill in the area touching the rear quarter panel. This cut loop is marked with a sticker that asks for the door sill to be cut to a specific depth. The ESA has determined that the placement of this cut loop under the vehicles body panel can vary dramatically and found this cut loop to be unreliable due to the fact that the wire is not marked and that the wiring harness cannot be visualized without extensive dissection. The OEM has removed this cut loop from its ERGs but the markings (stickers) still remain on many vehicles found on the roadway. (See Figure 2)
When to Shutdown:
- The choice to shutdown the high voltage and isolate the energy to the battery should be made wisely. Cutting the first responder cut loop causes additional damage to the vehicle but is critical to life/safety when the vehicles damage justifies the action.
- Calling the ESA for assistance will ensure that proper shutdown procedures are executed and that shut down procedures are taking when necessary based of the damage to the vehicles high voltage system.
- Calling the ESA every time mitigates liability, ensures safety and protects property. Save the ESA Response center number. 855-ESA-SAFE or 855-372-7233 – The call is always free
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