I think the lil white one is to make the Digiplex run at 2* timing. Been almost 30yrs. Can't remember.
Stuff not needed. Did you get the brakes sorted?
EDIT: Looked it up in service manual, big one is diagnostic, lil one is for advance to be 2* less at startup.
READ-----https://guzzitek.org/gb/ma_us_uk/Calif1000_1100_Atel(I-GB).pdf