If there is a severe short circuit wicking away enough current, idle rpm goes rough and lower, oil light comes on, engine stops. High beam indicator shouldn't come on unless headlights and high beam are on.
Our 93 Lebarron failed to start once. When I jumped it off it ran but I could step on the brake pedal and it would stumble. Yup, draw from brake lights alone was enough. I did manage to drive it home in a cold rain without headlights or wipers. The short was inside the battery. I've seen similar short inside the alternator too but... high beam indicator wasn't a player in either case. It is a clue to where the fault is in this case.. in my opinion.
