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Electric issues - alot of things not working

Posted: 04 Apr 2017 21:35
by drascol
I recently purchased a 1980 Datsun 510 Hatchback in an auction. I don't want to go too much into the transaction, but I will say that it was very, very messy, costly, and when it was finally over, I realized there was quite a few problems I didn't get to identify before driving away with it because of the situation.

I'm trying to figure out what's keeping all the headlights, break-lights, emergency blinkers, horn, overhead interior light and cigarette lighter from not working. Is it at all common for this model's 510 to lose power functionality in all of these areas?

Turn signals, AC, seatbell light, and clock all work (although the digital clock always resets to 1:00). Car runs ok. Can any 510 fans help me understand if I need to have the thing rewired, or if there's a simple problem with it causing all of these issues? I'm a novice and this is my first car. I'd love to be able to fix it myself, I just need some ideas or a lead to know where to start searching first. Thanks

Re: Electric issues - alot of things not working

Posted: 05 Apr 2017 08:43
by RMS
im not an HL510 guy but with most cars that have sat, a good cleaning of grounds and connectors is the first step in sorting out electrical gremlins .remember that just because a fuse looks good dose not mean it is good. aftermarket stereos and alarms are often the source of problems. look for scotch locks and splices.

Re: Electric issues - alot of things not working

Posted: 05 Apr 2017 16:38
by drascol
Thanks for the insight. Honestly I have no clue where to begin at finding all the connectors that are deep inside it. I really hope I don't have to take apart the car too much, but maybe that's in order! the wiring is kind of nasty, but I don't see any splices

Thankfully no aftermarket crap is in here. It's pretty much stock, which I love. No radio at all. I've been told bad relays could be a culprit, but first I'm going to get a full set of new fuses and see if that helps any of the problems, and also get the alternator checked. Hope that solves atleast one of the issues!

Re: Electric issues - alot of things not working

Posted: 05 Apr 2017 16:57
by datzenmike
Headlights, brake lights, horn, interior lamp, 4 way flashers are all items that will work without the ignition on. Headlamps usually have their own fusible link and is powered at all times through the headlamp switch. The others probably are on a section of the fuse box connected to it's own fusible link. The third fusible link goes only to the ignition and everything on it like wipers, heater, turn signals are turned on and off with the key.


The fusible links are always located close to the positive battery terminal. There may be a heavy gauge wire (besides the big cable to the starter) with the fusible links connected to it. In all cases the fusible links will have plastic connectors on their ends so they can be removed and replaced. The are color coded to indicate the rated amperage they carry. Usually Black (80 amp) and Green, (40 amp) maybe red. (50 amp)

The fusible link protects the long wires to the ignition and fuse box in the event of a catastrophic accident where the wires would be crushed and grounded. In this case enough current flow from the battery would heat up the wires like a toaster and cause a fire. Fusible links will carry a high current load for several seconds before melting and breaking the connection. Fusible links are not just wires but wires with a special Hypalon plastic coating that is fire resistant. If you inspect a fusible link it may appear melted and burned. If not melted the wire inside may be and when handled it will be crispy. If replacing use only fusible link wire.

Re: Electric issues - alot of things not working

Posted: 05 Apr 2017 18:22
by okayfine
Would also recommend tracking down a wiring diagram for your car. Lots of factory manuals have been scanned at You'll also need a Volt/Ohm Meter (VOM) and some basic wiring tools (stripper, soldering iron, e-tape, spare fuses). I'd also recommend giving your fuse box a vinegar bath (remove, submerge in vinegar for 10 minutes, rinse with water, air dry or hairdry, reinstall) - has been known to cure gremlins.

Though I agree with Mike that you have a bigger supply issue, but you're going to need all that anyway.

Re: Electric issues - alot of things not working

Posted: 10 Apr 2017 18:14
by drascol
So as an update:

I managed to get the headlights, breaklights, instrument lights ALL to turn on.. temporarily. If I turn on the headlights, then turning over the fuse box and bridging a connection between some of the fuses, all those lights seem to cut on instantly and stay on until turned off. Then they won't come back on unless I jump them again like that.

The culprit seems to be connected this white wire that connects to the back of the fuse box. Somewhere along the way, it isn't getting power somehow. this white wire seems to be connected to these three fuses that are closest to the steering wheel when the fuse box is seated correctly (the one on the far left seems to be getting power just fine in this row, but not the three on the right side).

The horn also works, but it is so weak and feight you can baaaaarely hear it. It's like a whisper, and its only active while the fuses are jumped like I described.

I'm not sure where this white wire leads, but I think that's the key to me getting these gremlins out.

Re: Electric issues - alot of things not working

Posted: 13 Apr 2017 17:44
by okayfine
White wire is larger diameter and separate feed into the fuse box than the bunched/plug wire sets? That's the feed into the fuse box (and, hence, your wiring harness) from the alternator. See Datsunmike's post above about the fuseable link that is inline with this feed from the alt.