This isn’t the case. Your general knowledge of the system is good, however, when the car is ‘cranking’ the Brake light warning indicator will illuminate, this is to show you that the light and system is functioning properly. When released (now run position) the only thing that should illuminate the brake warning light is a pressure imbalance (from the pro valve or distribution block), if the e-brake is engaged, or if you have a faulty switch in either.
That said, I’m wondering what, in the start function, grounds the brake warning light, in order to show the temporary illumination and its proper functioning.
Also, there is no ‘charging’ light on these cars, just an ammeter.
Both the brake warning light and oil light have power at the circuit board in the dash in the run position all the time but will only illuminate when the prospective light’s switch is triggered (oil or brake) which does the triggering by means of Ground.