Hi Dico,

The red item is a Dukes dual speed fuel pump.

The black item with the big heat sink is an AmeriKing dimmer for your lighting. Unplug it and see what dies.

The item with the red arrow is located at the end of an oil line is an oil pressure switch. Likely used to activate your Hobbs meter.

The silver unit looks to be a remote GPS (used to switch navigation data sources) switch OR, if there is a static line connected to the other side, it could be a blind encoder. Again, unplug it and see what dies.

Regards
Brent Regan