Ok your system has two switches one for each battery
The switches have either e or 5 wires and are DPDT momentary center off
The 4 wires are Positive (12 volts) Negative (Ground) Relay 1 and relay 2.
There may also be a 5th "indicator" if the switch lights up
You will need to figure out which wires run to the solenoid. These will have NO VOLTAGE on them when you measure with a meter.
But they will show continunity (Resistance other than open/zero)
Measure them to a known good ground for voltage.. Then find out which ones are ZERO volts to Known good ground (The remaining wire shoudl show battery voltage. mark it
Now measure between the "no voltage" on resistance.. Infinity. one of those wires is GROUND.. if you swap one wire for the 3rd and you still get INFINITY then the wire you did not swap is Ground.. USe a test light to check for current flow (hook clip to wire you think is ground and tip to the known 12 volt lead) Bright light = You got it
The other two should show a connection other than zero/infinity and they are the coil.
Now the switch wiring DPDT switches have six terminals
Power goes to one side center. Ground the other side center
Relay leads to the end (one on each side> and then two jumpers to the other end but CROSSED OVER.. IF the switch works as you wish (UP =Connects Down Disconnects GOOD. IF not Turn the switch over or flip either the Power/Ground or the relay pair.
how it works
THe relay is a magnetic latch.. Put power to the coil so it flows one way and CONNECT.. The other DISCONNECT.. That simple.
Home was where I park it. but alas the.
2005 Damon Intruder 377 Alas declared a total loss
after a semi "nicked" it. Still have the radios
Kenwood TS-2000, ICOM ID-5100, ID-51A+2, ID-880 REF030C most times