Dead Battery: What the Heck am I Missing?

[swissarmychainsaw]

1975 GMC 350/350 pickup
had it about 6 months, daily driver. When I bought it I put in a Brand New battery from O'reilly's

Yesterday it's a bit misty in the morning so I turn on my lights on the way to work. Yeah, I never turn them off.
Battery was totally dead, no dash lights, idiot lights, etc.

So at night, when I get off work, a buddy gives me a jump.
It takes a minute but I get it fired up and drive it on the fwy about 30 minutes home.
Park at my house, and shut it off. Decided I should pull up in the driveway and go to start it. DEAD.
No lights of ANY kind. FLAT DEAD.

HRM. ok. Pull it out, bring it to the garage and Put my Battery Tender 1.25A (for a motorcycle) on it and let it sit overnight.

In the Morning TOTALLY DEAD.
Battery Tender shows the red light (as in charging, but below 80% full).
Try and jump start it with the wife's car, no dice.

I say "hey this battery is junk" and take it to the store.
Dude tests it, says this battery is good but needs a charge.
I say, man, I don't think it is!

He charges it (during the day) tests is and says "good to go".

Bring it home, put in truck. SAME THING. DEAD. No lights at all.

Volt meter shows 14v.

Is there a main fuse I am missing somewhere?

I'm stumped.

The fuses look all ok. (thanks for putting them under the dash like that btw! yea!)

[Gregs71]

Could it be dirty / corroded terminals??

[mrolds88]

Put everything back together. Then starting at the battery, use your meter and go through the system. Start at the + terminal and the block. Then move through the system until you get a blank. Also check your terminal block on the back of the fuseblock.

[rs74]

My post didn't go through earlier. I would check your main battery cables first at the starter and where you ground is. Put your meter on the positive cable at the starter to see if you are getting a good reading there. Just to rule out bad cables.

[cadillac_al]

Pretty interesting. I didn't think you could boost a vehicle when the battery is so dead it won't light the dash lights. Something bust have burnt out. Just keep checking voltage , down at the starter and up to the firewall. I'm thinking either the fusible link down by the starter or that main fuse on the firewall.

I never turn my lights on during the day because I always leave them on too. The fog or rain would have to be pretty heavy for me to turn on my lights in the day daytime. I feel your pain.

[swissarmychainsaw]

Well, somehow, and it's obvious now...I blew the main fuse on the Firewall.

Found the one with the biggest wire and opened it up.
I don't have many of these old glass fuses, so I could only put a 10A in there for now, but that was enough to start it.

What are the others for?

[old Rusty C10]

someone prolly replaced a fusible link

[swissarmychainsaw]

I only had smaller glass fuses, which would allow the truck to start, but when I turned it off, it would blow the fuse!

Stopped at auto parts place this am and put in a 30A fuse, and it seems to
be fine now.

I would like to replace all the fuses with the newer blade type.
Easier to handle and more readily available I think. Is that worth the trouble?

Also, anyone know what those other fuses are for in the red circles?