Battery. Dual. Pros and cons. I have both.

[AuroraGirl]

Everything you've said makes complete sense, I just don't see it in the 1998 wiring diagrams. As you said, there may have been changes made through the years.

Honestly, the wiring diagram I posted (from the 1998 FSM) doesn't make sense for the Diesel or any situation where the LH (2nd) battery is required to supply starting current. In the diagram, the LH battery is shown wired via the stud on the underhood / firewall fuse, which connects it to the RH (main) battery (and then starter) via that LONG (8ga?) wire that snakes over the radiator shroud.

Maybe the diagram I posted is just wrong. Well anyway, it provides perspective.

heres a 1998 K2500 5.7 according to what I found

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starting circuit, that is

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heres a charging circuit

then I thought maybe the a cooling fan tie in may exist but I was wrong. but i found this cool thing about the aux fan trucks, powered by a relay I would assume most trucks have(?) just the unused leg of it?

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