I have a 2003 Suburban 1500 LT Z71 and I am installing a DC-DC charger in it which has a power sensing lead that turns the charger on. Basic instructions tell me I need to connect that lead to a switched circuit. However, I would prefer to NOT have the charger turn on when the key is switched to the ON/ACC position, rather when the engine is actually running and the alternator is producing power. Does anyone know if there is such a circuit available and if so, which fuse it may be running off of? I have included the instrument panel, underhood, and relay block diagrams below for reference to help make discussions here easier based on the fuse numbering and labels if that helps.

TIA

2003 Chevrolet Suburban Fuse Diagram for instrument panel fuse box

2003 Chevrolet Suburban Fuse Diagram for Underhood fuse box

2003 Chevrolet Suburban Relay Block