Charging circuit - reduced load on ammeter circuit

IMO
I just put relays on the major players; feeding them power from either source, and triggered them by either the run circuit or the headlight switch. Ammeter-Guage still reads as designed.
If you trigger the blower off the headlight sw, then you can use that circuit as a DRL. If you run the headlight sw off a relay triggered by the run circuit, you can even make it automatic. Relays are very useful.