Hey everyone, been keeping my '78 datsun ute alive for the past few months by the skin of my teeth and it finally kicked it.
The ute will run fine if it is jump started, but when driving i lose the radio and headlights dim, etc. However when I try to turn the key over, the electrics turn on, but i get the clicking sound suggesting the battery is dead even though i have changed the battery just to be sure.

Anyway to anyone out there that can help me would be much appreciated! :)
Okay so, i've narrowed it down to a few problems it possibly could be
- The alternator: The original alternator died earlier in the year and I replaced it with a recycled alternator (the cheap option). Would love to know if it is just because I went for the cheap option?

- The small positive wire trailing off the main positive cable connected to the battery, appears to overheat and break every chance it gets and honestly I've just been soldering it back together. I recently tracked the wire into the loom/harness it connects to, and it splits off into 3 wires, 2 of which proceed into the firewall and into the cabin, while the other continues towards the positive post of the alternator. Would love to here some ideas about that

- A particular fuse: I wouldnt have thought that the datsun would have an alternator fuse, but I could be wrong. The only fuses I can see are the classic cylindrical ones underneath the dash on the drivers side.

-Anything else i couldve left out?

I think thats everything! If anybody could help me ASAP, it would be greatly appreciated!

Cheers,
Sam

That overheating wire sounds like there's a short somewhere. Do you have a multimeter? The continuity tester is pretty handy for finding shorts. A wiring diagram (which you'll find in the tech wiki) will also help. You can also check the voltage of the system while it's running with a multimeter.

Is the charge light on while the engine's running? Assuming it's wired to the alternator it'll tell you if it's charging. (The light stays off if the wire's disconnected.)

As with anything it's a process of elimination. Start with determining if the alternator's working and if the battery's healthy. Then look for shorts, burned fuses etc. If you can't spot anything you might try pulling a single fuse at a time and seeing if the problem goes away (this will pick on particular circuits).

Re the alternator fuse, I believe there is a fusible link to the alternator, I can't remember where, DD is usually on top of that sort of thing.

Hope this helps.

I wish I still had my multi metre but my mate backed over it a few weeks ago which was really annoying! And thats what i was thinking but Ive followed the wires along and the only place there could be a short is where the wire splits into 3 as there is no insulation around the wires, just bare wire.

The charge light comes on when the electrics are on, with the engine running the CHG light turns off immediately unlike the OIL light which stays on for a few seconds then turns off. Is that a sign that something isnt right with the alternator? Thats if the car has been jump started of course.

I've hooked everything back up and tried it, the electrics came on, turn the key over and it I get the solanoid clicking sound but then i get this weird whurring/scraping/grinding noise coming from near the dizzy and starter motor? I did the hammer trick on the starter but the sound was still there. Also the OIL and CHG lights are extremely dim when I try to turn the engine over and hold the key in that position. Any thoughts?

Cheers mate appreciate it

My battery started running flat every day or so, turns out the wire going to the charge light had been somehow ripped out so it wasn't able to charge the battery (so the auto-sparky said).

The 3 positive wires - 1 goes to + on Alt as you say.
1 goes to ignition barrel (at least on my B110 it does but it wouldn't take much convincing to make me believe a previous owner was worse at wiring than I am...)
Not sure on the last one. Dash maybe, or the head unit?

I've had the battery on a charger overnight and when i hooked it all up, the engine was able to turn over but wasnt able to run. I tried it a second time and it began to run. I'm assuming the only reason it was able to work and it will soon cut out in a few days again, is because the battery was at its maximum charge capacity?

I have not touched the wiring again, so this is doing my head in haha