Dash Oil and Brake Warning light - how are they triggered in the start function?
Here's a start (no pun intended).
1970 Plymouth FSM
Feed to the lamps is with the key in run (I1) -> J2 -> G5.
G6 ends up here with no splices.

So far,
if the oil pressure warning lamp flashes during start - its likely to be a brief back feed through the ballast. Would think it unlikely that current can be sustained through start when there are other paths to ground available.