Originally I had planned to wire the lights directly to the battery, ... the same way that a car’s brake light switch works. ... (Used in the wiring harness) Momentary switch $10. Magnets $12 ...

The diagrams and photos show how to wire up the fuel pump and oil-pressure switch to a commonly available, industry standard, ISO-type "1 Form C single pole/double throw" (SPDT) relay.

In a dream world, cars have no wiring at all ... that require only a momentary switch to operate. It's a light and simple system. We killed the battery playing with the car and found out the ...