I connected my xac and relays to power through the engine run switch… repurposing it. The original engine run wires were connected to a simple reed relay which was powered on by the engine run switch… does that make sense? Basically the engine run switch connected power to the reed relay (connecting the original engine run wires that were connected to the engine run switch), and to the xac and power bus for dpdt latching relay and the automotive relays used to supplement the key switch.
The result is that I flip the engine run switch and that powers up the xac and “primes it” to act as a “key” when an authorized tag is scanned. More importantly, to shut it all down, just turn off the engine run switch and everything shuts down including the latched relay.