04 1/2 ton underhood fuse box issues

[Marv D]

Will try to make this short.. My 02 4x4 went to the shop friday acting like a broken battery post (12v until you hit the key then 2v),, But the battery is fine, the cables are clean, as are terminals, bla bla,, Put a meter on teh battery when turning the switch and the battery shows 12.7 with only a slight drop,,,, but no start and everything goes dead inside. Headlights stay bright,, all power windows and everything acts like a good fresh battery.

I checked the power lugs under the cover of the fuse box,, full 12v there,, I gave up and towed it to the shop. A day of tracing the problem expecting the ignition switch,,, and he found a melted terminal under the bottom side of the (underhood) fuse center. Apparently the cabin gets power to the ignition switch from TWO legs,,, one of them had overheated and melted the fuseblock.

The question here is,,,

Has anyone had any issues like this. The only thing I can think of is we have multiple electronics we have to charge batteries for and use a small inverter plugged into the indash lighter / charger ports. The wire has never felt hot to the inverter or the charger) and the batteries are similar to 4 AA. Otherwise I'm at a loss.

GM wiring and electronics really takes a beating here in the Az desert at 100°+ all summer but DAMN they sure seem to be with NO durability in mind any more.