[Kor3y101]

Hey there.

So I've been having a few electrical issues and I'm stumped by it all. Before taking it to an auto elec, I thought I'd see if anyone else has had this issue.

On Thursday, it stormed pretty heavily here, I drove home from work in it and all was good. The next morning I start my car ready for work in 30 seconds later everything stopped and nothing had power. Google search showed it was a fusible link. So I ran a wire straight from the alternator to the positive terminal and alas, it turned back on (the fusible link was still attached at this point)

So this afternoon I took off the fusible link and ran a glass fused wire from the alternator to the battery terminal, and nothing happened. Double checked all my connections in the solder and it was all good. I checked with the multimeter and I was getting 12v at the alternator. So I put the fusible line back on by its own, and still the same issue. So I decided to put both on to see what would happen. And it worked, but only when both were touching.
So after much cussing and head scratching I gave up. Unplugged all the cables off the alternator and as I was pulling out the keys from the ignition I turned the lights and it worked, with no cables connected to the alternator.

I then put the original fusible wire back on the alternator, turned the car off and tried it again and it worked and was running fine as if nothing had happened.

Thinking it may be a dying alternator, I checked it's charging volts, and with its headlights on it was charging at 13.7-13.8v
Is this normal?

I also found a slight coolant leak on my top hose that appears that it might drop into alternator. Slight as in a tap drip every few minutes.

I've tried searching but can't find the schematics for an '84 sierra. Does anyone have a link to it. And does anyone know what my issues might be?

Thanks!

[shep]

The fuse link is the power feed to the fuse box and well everything. Make up a wire to go from the battery to the fuse link plug(the White one 8 or so cm from the battery) and see if that fixes it

[Kor3y101]

Cheers Shep, but I have looked everywhere and the only white plug I can find is the one coming off the alternator charging plug. There is no green cable I can see that comes off the battery. I saw the thread on here about this topic but it seems that mine looks nothing like that..

[shep]

It is normally on a wire off the + battery terminal and there is a plug before the wire joins the wiring loom.

[Kor3y101]

That's what I thought.. But no luck.. There is a black cable that is above the thick cable on the terminal that joins into the loom, but there is no fusible link plug on it. Are the looms different in the 85' onwards?

[Kor3y101]

So after reading some more it appears what I was disconnecting was not the fusible link, but just a plug from the alternator to the wiring loom. This isn't the correct thing right?

My car does not appear to have any link between the fuse box inside the car and the battery. Unless there is something I am missing? Going to double check all my earths are nice and tight, but I don't know what else to check for now.

[jdk81]

Take a pic, it might help us identify dodgy diy wiring etc

As shep was saying there should be another plug to the white with yellow stripe wire, near the battery/brake booster.
Its a thickish wire comes off the positive terminal and has a fusible link, then goes to the same type and style of plug as the one you disconnected near the alt.

[Kor3y101]

Okay, so here are some photos;

So as you can see, there is a thick(ish) wire that comes off the + terminal that leads into the loom, and possibly back out again which then runs up towards the firewall.


Overview ;


Thickish wire that looks like it should be fused?


I believe this is the same wire that runs out of the loom a couple cm down again and goes to the firewall



Now, I was thinking about this last night, and even if there is no fusible link (which there should be, perhaps someone has done a dodgy job) this shouldn't interfere with my car as there is nothing to blow before the fuses/major components.
I'm wondering if a bad earth could be the suspect of my woes?

[shep]

Some of your proble is that there is no earth to the firewall. Can see what is left of it but it isn't compleat. All the earth to the body is going through the steering colum

[shep]

In the last pic what is the wire that can see a bit of below the airbox clip

[Kor3y101]

Okay, so I should add an earth from the battery to the firewall? Looks like there was one some time ago but has been cut.

The wire just below the clip in the picture is this one ;


It comes out of the loom and runs into another part out if that runs along the firewall and into the car on the passenger side.

[jdk81]

As shep said, check the earth wire.
You need a good body to battery earth.
Imo earthing the chassis is also a good idea (chassis - body, chassis - engine, or chassis - battery)
IIRC tail lights are earthed to the chassis, but there is no proper connection and i have had issues in the past.

Re the fusible link
Pull that bit of tape off near the brake fluid reservoir (below the zip tie), which is binding the two black wires together.
IIRC the plug should be under that.
If its not fused, fuse it.
Someone has modified things there.

I have had issues in stupid heavy rain that blew fuses, as the water got down to the fuse box, then drips on the accelerator pedal.

In this case i think it came through the softtop windsreen seal (where it folds), as the plenum (slotted venty thing) had been cleared of leaves, gum nuts, bullet casings and such.

My tintop leaks here and i think its the windscreen seal (already checked the plenum).

Good luck

[Kor3y101]

jdk81 wrote:

As shep said, check the earth wire.
You need a good body to battery earth.
Imo earthing the chassis is also a good idea (chassis - body, chassis - engine, or chassis - battery)
IIRC tail lights are earthed to the chassis, but there is no proper connection and i have had issues in the past.

Re the fusible link
Pull that bit of tape off near the brake fluid reservoir (below the zip tie), which is binding the two black wires together.
IIRC the plug should be under that.
If its not fused, fuse it.
Someone has modified things there.

I have had issues in stupid heavy rain that blew fuses, as the water got down to the fuse box, then drips on the accelerator pedal.

In this case i think it came through the softtop windsreen seal (where it folds), as the plenum (slotted venty thing) had been cleared of leaves, gum nuts, bullet casings and such.

My tintop leaks here and i think its the windscreen seal (already checked the plenum).

Good luck

Awesome. Thanks for all that. I'll unwrap the tape and double check, if not. I'll fuse it. I do get a drip on my pedal in rain too, I put it down to the soft top. But will definitely check the plenum isn't full of rubbish.

I'll also put an earth to the body this morning to see how it all goes. It starts and runs fine now, I'm possibly thinking when I took the battery out to fit my bullbar the earth may of got knocked in the terminal somehow and popped out for some reason.. But not 100% sure.

Thanks!

[Kor3y101]

So I've undone the tape and found this ;


It looks like it's a fusible link but can't say 100%. So to be safe, I'm going to cut it out and put the glass fuse in and solder it back up.

But it all seems to be working again.. Could it of been a mix of water and a loose ground I wonder.

[AckerDackerly]

The black wire that you are holding in the picture of the Positive terminal ("+" cast into the top of the battery case) is, I suspect, what should be the "fusible link".


If you can trace it to one of the firewall plugs that has a bundle of wires passing through it with this wire, you have found the power cable that feeds the back of the fuse box. Somewhere before it goes into the firewall, it should also branch off to the alternator.

It is VERY unusual that this wire happens to be black. It should be white with a yellow tracer on it. It NOT be black or green - common colours for ground or earth wires.

My guess is that it is not the original wire (the actual "fusible link wire") and there is a defective splice somewhere along that wire before it splits off to the fusebox and alternator. I would also give a thorough cleaning of where it attaches to the positive terminal clamp.

Take a look at:

http://acksfaq.com/diagram_color_86-88_sam.htm (SJ-413/Samurai diagram)

or

http://acksfaq.com/pdfs/86-87sam15-7_end.pdf (SJ410/1-liter narrow track) on page 21-10 - showing a picture of the fusible link


What do the other red wires that are connected to the "+" terminal go to? Winch? Audio system?


I hope that this helps!

[Kor3y101]

Thanks Ack, I've taken off the terminals and given them a good clean, everything seems to be working fine now.

The other red wires go to a Acc plug in the back and one for power for the temp sensor.

I'm really not sure what the whole issue was. I haven't really done anything to it that would make it work other then cleaning the terminals. But I had only done that this morning, but it had started to work prior to that.

[shep]

Bet it is the body earth. The only way the body is grounded when the firewall ground is missing is through the steering biscuit so there is Prob a bit of slop stopping a good contact

[Kor3y101]

No worries shep. I'll definitely earth the body to the battery from the firewall. Hopefully that will aid with some of my gremlins. Drove to car to and from work today (40 mins in total) and it didn't skip a beat.
Next on my list is an alternator upgrade as I now have a Light bar to mount also (162W)

Thanks for all of your help guys!