I am trying to locate a 12v power source controlled by the ignition switch without having to go all the way back to the switch itself. Not having the best luck so asking for any guidance anyone can provide. Thank you in advance!
The brown lead on the starter solenoid is hooked to the ignition coil and is switched 7-12V (start: 12V, running: 7V). It should not be used to supply much current. However, you could use it to control a Bosch-style Mini-ISO relay to provide switched battery power.
Be sure to protect the circuit with a fuse/circuit breaker between the battery and the relay input (pin 30) for safety. The ignition solenoid brown wire connects to pin 86, pin 87 for the output, and pin 85 to ground.
A CIT A91AC12VDC relay conveniently has a built-in socket for a fuse.