By trigger wire, I mean the wire that triggers, switches, or actuates the relay. Not its power feed, just the switch wire.
My overhead spotlight switch works as per factory. But now when the factory spots light up, so does the roof light.
I did this by taking a feed from the spotlights positive connection. This power wire is only live when the factory spotlights are illuminated. I then connected this into the EXT2 25A relay.
So now that relay no longer switches on off by the roof ext2 switch.
That relay now switches on and off the moment the factory spotlights do, so in effect the factory spotlights and the roof light bar now operate in parallel, together, as one, at the same moment in time.
I hope this answers your question