Quote: Originally Posted by aoLhaTer
Im not really understanding what the relay actually is
Excuse my ignorance
I guess you can think relay as automatic switch when it get some signal.
In this case, when the relay get power from reverse light (which only turns on when shifted rear), circuit is switched to 87 instead of 87a.
When power is off, relay is at the 87a position and that makes Cheese box circuit open. When relay gets power, it switche to 87 and that makes cheese box closed.
FYI, when cheese box is open, VGA is displayed on the monitor and when it is closed VIDEO is displayed.