Electrical system dead except for horn & hazards

[KJones]

Came back from vacation and 2003 Vibe GT wouldn't start, no instrument lights or buzzer when key was inserted. Went to jump start and as soon as connection was made the horn and headlights came on, each time. Hooked charger up, dead battery began charging ok (no horn or headlights). Tightened a loose battery cable and fully charged battery and now car acts dead except horn and hazards work, no dome light, headlights, instrument lights, hatch release, starter. Have power to fuse box under hood, wasn't able to check fuse box under dash yet (could they have made that more inaccessible).
Haven't found if there is a main fuse or fusible link somewhere (if so where is it?), but power to that panel makes me think maybe not. Any help is appreciated, thanks!

[joatmon]

I attached a PDF of the primary power distribution schematic, its for an 03 matrix but it matches your 03 Vibe

Power comes from the battery, gets to the horn and hazard fuses since those things still work. I'd look at the 100A Main fuse. Its bolted in from underneath, but you might be able to see through a clear plastic cover. Also, try pulling the fuses that the 100A Main fuse directly feeds, and see if you get 12V on one side of any of those fuses. If you do then the Main fuse might be ok

Not saying this happened to your Vibe, but folks here have reported blowing the 100A fuse by trying to jump start a Vibe unfortunately with the cables crossed. In some of those cases, some other fuses got popped as well. I've never had to replace one, but reports are that fun is not involved

[KJones]

Thanks, but exactly where is this 100 amp fuse? Looking at the positive battery cable it goes directly to the fuse box on my 035

[KJones]

Thanks, but exactly where is this 100 amp fuse? Looking at the positive battery cable it goes directly to the fuse box on my 035

[joatmon]

my bad, I said Main fuse, but its the ALT fuse in the underhood fuse block

100A.jpg (43.09 KiB) Viewed 1214 times

100A-b.jpg (56.35 KiB) Viewed 1214 times

edit - this video offers some insight into replacement
https://www.youtube.com/watch?v=5rKZi4e4lPQ

[KJones]

Yep, that's popped! Thanks!
What's the trick for pulling it out?!? Oh, never mind, I see it's bolted from below.

[KJones]

Tardy update: It was that 100A fuse, and it was a pita to get that bolt under it off and back on.

[tpollauf]

A six month delay in progress report BUT well worth it. Now if you knew exactly what it was that blew this fuse? You don't want to go through this again. Just curious. Thanks