Full battery but no start no nothing

[f2502011]

Battery fully charged but no lights no start nothing. Battery connection is tight. Checked ground it’s tight. Haven’t changed anything did just fine last time I cranked it. Any ideas? It’s completely dead.

 

[71 CA Bronco]

My first thought is to check to see if it has a master fuse. Could be blown. If so you will need to figure out why it blew. I would also try to turn it over off the starter solenoid using a screw driver. Of course I wouldn't think a bad solenoid would kill the lights.

 

[f2502011]

Where might a master fuse be? Fuses inside glovebox all look fine but don’t see a master fuse.

 

[DirtDonk]

There’s no master fuse in a factory harness, however there is a fusible link (which is the same thing basically) attached to the battery side of the starter relay/solenoid.
If the harness has been replaced though, you most likely have a main fuse over near the starter relay.
Is it the original harness?

Generally speaking there is only one other thing that can kill all the power to the vehicle. And that’s a battery cable. Positive or negative.
If you checked everything, and nothing works, including heater motor, turn signals, radio, flashers, horn, headlights etc., then it’s either a battery cable or that main black wire at the starter relay.
Aftermarket harnesses typically use red wire, but the factory used black.

 

[DirtDonk]

Actually there is one other thing. It’s still that same black wire, but there is a main connector behind the ammeter in the instrument cluster and if that becomes loose, disconnected, or has just built up too much rust, it can also kill all the power.

 

[Rustytruck]

Check the ground wire where it bolts to the engine block. also remove the battery cables and clean the ends and the bttery posts to white metal. No corrosion or black crust. Have you tried to jump start that will bypass bad battery connections.

 

[Broncobowsher]

There are 2 grounds to worry about. The big one to the engine to handle high amp loads, mostly starter but alternator as well.
Then a lot smaller one to the body that handles all the little things like lights and the starter solenoid.

Have you had the dash apart, there is a main feed wire that goes through the inductive loop of the alternator, that has to be connected.

 

[f2502011]

The connector for main black wire that bolts to the positive side of the starter solenoid and positive battery cable that sends all the power to everything gave up the ghost. Guess the connector had just become too brittle over 50+ years. I made a new connector and everything is back up and running.

 

[DirtDonk]

Fantastic. Good find.
If you ever have a case where you hear the first click of the starter, then everything just goes dead. Suspect a bad battery cable.
If power eventually comes back mysteriously and then does it again a few days/weeks later, then just replace the battery cables. Because it's almost guaranteed to be the problem.
Not necessarily the starter cable, as that won't kill power to anything but the starter. But if you're replacing the battery cables anyway, might as well do all three since it's not that big of an expense.

Paul

 

[f2502011]

Fantastic. Good find.
If you ever have a case where you hear the first click of the starter, then everything just goes dead. Suspect a bad battery cable.
If power eventually comes back mysteriously and then does it again a few days/weeks later, then just replace the battery cables. Because it's almost guaranteed to be the problem.
Not necessarily the starter cable, as that won't kill power to anything but the starter. But if you're replacing the battery cables anyway, might as well do all three since it's not that big of an expense.

Paul

The main wiring harness is an original. All the other wires and cables that are visible larger and stand out are new either NOS or accurate reproductions. My repair of the main hot wire looks good and professionally done but not completely correct since the connecting end is different and not the original one with an orange insulator on the outside. Would like to get an original harness I could harvest the correct original wire from and splice it into mine.

 

[DirtDonk]

Nice idea. Plenty of old originals running around now that others are changing to new.
In the meantime, a slightly more "original" looking setup might be one of the readily available fusible links from the local auto parts store. Or is that what you got with the Orange insulator? I know the originals were black, but if you did that type it's at least a visible factory 'style" fusible link.

Good luck. Where are you located? Someone nearby might have one laying around. I have one for the smaller ACC wire on the back of the ignition switch I've been meaning to use, but think I've already tossed all the main ones in the Black wire.

Paul