Good diagram in the car = good idea.
I've only had one "serious" problem with the ForkenSwift in 5+ years - a poorly routed (my fault) small-gauge wire (for contactor control, if I recall) chafed and shorted out. It released some smoke & stink in the engine compartment, and when I caught a whiff I immediately pressed my clutch-based emergency pack disconnect and stopped at the side of the road to investigate.
I spent longer "re-figuring out" how the melted wire fit in the whole system than actually fixing the problem itself. (I was able to drive home.)
At the time, I wished I'd had a handy circuit diagram posted under the hood or in the glove box. Of course, I still haven't done that. I'm not that organized. And slow to learn, apparently!