Complete Electrical power loss (2 Viewers)

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Buffchief

Buffchief

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I was removing my alternator last night and in the process of disconnecting my battery ground and hot cables I touched a wrench from the ground cable to the alternator hot supply wire with a spark !!! I went ahead and removed the alt and then checked to see if any fuses were blown. Nothing looks bad but I have ZERO power now with the ignition key. Checked the fuses and they all (that I know of) are good. Looks like the disable link is good as well. Any ideas?
 
Not sure if this applies to your rig as you didn't mention your year (mine's a 79), but you might check the fusible link in the wiring harness between the alternator and the battery. I also seem to recall an inline fuse between the alternator and fuse block in the engine harness as well.
 
CruiserInProgress said:
Not sure if this applies to your rig as you didn't mention your year (mine's a 79), but you might check the fusible link in the wiring harness between the alternator and the battery. I also seem to recall an inline fuse between the alternator and fuse block in the engine harness as well.
Click to expand...
Yeah that's what I meant. Mine is an 80
 
I should have power for lights etc... without the key in the ignition correct? Always have before. Now nothing at all. No brake, blinker, dash etc...
Complete loss of power. New battery fully charged. All I did was touch a wrench on the battery negative to the alternator hot supply when this happened!
 
That was a dead short, the full amperage of your battery could flow in an instant. The weakest links usually go first.

I would start looking for the fusible link - it will be bubbled up insulation as a giveaway it was consumed. Pull the battery ground then pull the fuse box and look at the connection to the clips. Maybe some are burnt off/corroded.

VOM and a test light are the tools of choice. Clean/inspect the battery terminals, then clean the ground from the -neg black terminal to the engine/frame/chassis.
 
FWIW, the power your missing is usually tied in at starter, possibly you need to connect two wires from back of alt to get power, should be at starter but hey, never know.

1980 fj40 wiring.gif
 
See the WHT wire runs from starter to ammeter then back to Alt, Ign swith, & fuse panel, find that white wire and why it has no power. I dont know if the ammeter would fail when you arked it and not let power pass thru ?
 
You haven’t said, but I assume you have an alternator that tested good, put it on and connected the wiring. Any movement in the amp gauge when you turn switches?
 
charliemeyer007 said:
That was a dead short, the full amperage of your battery could flow in an instant. The weakest links usually go first.

I would start looking for the fusible link - it will be bubbled up insulation as a giveaway it was consumed. Pull the battery ground then pull the fuse box and look at the connection to the clips. Maybe some are burnt off/corroded.

VOM and a test light are the tools of choice. Clean/inspect the battery terminals, then clean the ground from the -neg black terminal to the engine/frame/chassis.
Click to expand...

Ditto. If your fuse block looks OK, start looking for your fusible link. If your wiring is oem, follow the heavy white wire with a blue stripe, between the battery and alternator, probably wrapped in the harness, with connectors on each end of it.
 
igotta40 said:
You haven’t said, but I assume you have an alternator that tested good, put it on and connected the wiring. Any movement in the amp gauge when you turn switches?
Click to expand...
So I do have it off at the moment. I had it rebuilt and installed it yesterday and all was great, the shop that fixed asked me to bring it back in because he wasn't sure his soldering gun was working correctly after I had left his shop. That's when I arved it. He has it now going through it. But, while it was in the shop I could still start the engine and run everything without the alt with the charger connected. Now I have absolute nothing at all. Not even a brake light when I hit the brake!
 
CruiserInProgress said:
Ditto. If your fuse block looks OK, start looking for your fusible link. If your wiring is oem, follow the heavy white wire with a blue stripe, between the battery and alternator, probably wrapped in the harness, with connectors on each end of it.
Click to expand...
The fusable link looks fine and not bubbled up. I tugged on it and its not loose. I checked continuity of all the fuses and they all check good. I don't know if there is a hidden fuse somewhere or not. Maybe ground suddenly went to crap with the ark?
 
CruiserInProgress said:
Ditto. If your fuse block looks OK, start looking for your fusible link. If your wiring is oem, follow the heavy white wire with a blue stripe, between the battery and alternator, probably wrapped in the harness, with connectors on each end of it.
Click to expand...
 
Buffchief said:
The fusable link looks fine and not bubbled up. I tugged on it and its not loose. I checked continuity of all the fuses and they all check good. I don't know if there is a hidden fuse somewhere or not. Maybe ground suddenly went to crap with the ark?
Click to expand...
Good news about your fusible link being ok. I'd double check it with a meter.

If your 80 is wired like my 79, there is a single in line fuse, probably hidden in the engine harness around a foot from the firewall. You should see the bulge.

There is also a double inline fuse in that same area, but that only goes to your ammeter and back again. It would not affect system power.
 
Last edited:
I checked the fusable link and it looks good. Not sure how it's supposed to be tested!? It's intact and not bubbled
 
CruiserInProgress said:
Good news about your fusible link being ok. I'd double check it with a meter.

As I mention earlier, there is another in line fuse, probably hidden in the engine harness around a foot from the firewall. You should see the bulge.
Click to expand...
I know there are two together and one single in plastic cases. They checked good. I'm going to check grounds... Even though they have all been redone lately. Never know
 
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