That character could use employee diagnostic access into the cars as they are always on the Internet. SSH into them, get into the battery controller and do myriad things. Set the thermal management into permanent heat mode. Disable thermal management 100% for the next time the car is driven so it can’t cool the batteries (good for getting rid of pesky rodents like muskrats that try to live in them.) Mess with the charge controller in general so it overcharges, undercharges. You name it. All sorts of fun things one could add to that book depending on your plot.
Make sure while your character is hacking the battery controller though, that they set the car stereo to play Dragula by Rob Zombie at full volume. For effect.
These idiots were dumb enough to design Teslas like computers rather than cars, so a whole lot of stuff was designed like a crappy cell phone rather than the proven design principles of automotive engineering.
Worse, Teslas are designed like computer software rather than cars, which is why they are so dangerous and terrible, as software development processes are absolutely horrible for things that actually matter, especially when compared to existing vehicle engineering principles.
I feel dirty cross-linking to that other place but check out how/where they locate the brake lines. A nice convenient rust-prone place, only accessible by removing the battery. Apparently the design has become even shittier since.
https://old.reddit.com/r/Justrolledintotheshop/comments/1j8sh8c/thx_for_making_me_take_down_the_battery_for_some/