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@gwri8, excellent! Glad we could solve a long standing issue. But I gotta ask... Did I pull the fusible link caps off your car in Atlanta and have a poke around? I know I messed around with the fuse block in the footwell and the multi-function switch on the steering column, but did I get up into the engine compartment? If so, I hope I would have noticed the links in the wrong positions. At least I hope I would have. I know it was a little drizzly at the time and we were rushed for time, but still.

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15 hours ago, wal280z said:

can we assume that the carry-over of the mis-placement in the 1977 diagram to the 1978 diagram? Seem logical. It's happened before.  That said, I don't have a 1978 harness to trace or verify the placement of said links.

Yes, I do believe the mis-placement did carry over from 77 into the 78 year. I think the location of the biggest (black) link never changed. I think they got it right on the diagram in 76 (right front), and then screwed it up in 77 which carried into 78.

It would sure be nice if any other 77 or 78 owners could verify the position of the links just for additional data points. I know I've checked my 77 and positively determined the positions of the links. And I know that @240260280 did the same on his 77 some number of years ago. But I don't have any hard 78 data points.

So for any of you 78 (or additional 77) owners out there who would like to participate? The easiest way to verify the link positions...

Turn your headlights on.
Remove the link that is closest to the fender and closest to the firewall (right rear) fusible link and the headlights should go out.

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17 hours ago, Captain Obvious said:

What change? I'm not sure what change you're talking about. The 77 and 78 manuals both look the same as far as the links go.

If you've got a 77 or 78, the links should look like this:
77-78links.jpg&key=600e9d6accac5e957e40b

My 5/77 is this exact way.

 

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Here's another thing to worry about, and one I haven't found an easy solution for - are the red links that many of us have on our cars in the "Br" spot 0.33 mm^2 like they're supposed to be or are they 0.69 mm^2 like the atlanticz.ca link shows.  I have a newer thicker red link and an older thinner red link on my car in the two Br spots.  I haven't fixed it but might if I knew where to get bona fide 0.33 mm^2 links.  That would be part 2 of the question.

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3 hours ago, Captain Obvious said:

@gwri8, excellent! Glad we could solve a long standing issue. But I gotta ask... Did I pull the fusible link caps off your car in Atlanta and have a poke around? I know I messed around with the fuse block in the footwell and the multi-function switch on the steering column, but did I get up into the engine compartment? If so, I hope I would have noticed the links in the wrong positions. At least I hope I would have. I know it was a little drizzly at the time and we were rushed for time, but still.

Yes, You, Wayne and I pulled the caps and "kind of discussed it" just ever so shortly.  I had a red link in the forward position at the time,  Wayne wanted me to switch to the dark side and replace the fusible links with something else,  plus being in huge parking lot in ATL at at National car show, drizzle, It was about lunch time, probably some gravity warps going on and my recently discovered short attention span was present. 🐿️  I think we all deserve a pass..... 😉

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OK. At least we talked about it a little. I remember that at the time, the priority was addressing the headlights so you didn't get caught in the dark. We may have glossed over the fusible links with "here's something else to take care of when you get a few spare minutes" or something like that. I'm just glad we could get a handle on the intermittent headlight issue and get you home with a definitive answer to what was causing the problem.

Yeah, I know @wal280z is all dreamy about the fuse replacements (note that I didn't say "upgrade" ) for the stock system. He's that kind of guy. Lives for the bling.  ROFL

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7 hours ago, Zed Head said:

Here's another thing to worry about, and one I haven't found an easy solution for - are the red links that many of us have on our cars in the "Br" spot 0.33 mm^2 like they're supposed to be or are they 0.69 mm^2 like the atlanticz.ca link shows.  I have a newer thicker red link and an older thinner red link on my car in the two Br spots.  I haven't fixed it but might if I knew where to get bona fide 0.33 mm^2 links.  That would be part 2 of the question.

I replaced all my fusible links a little while ago (still need to post up a public service warning thread about that whole thing, but...) and I believe I saved my old ones. I'll take a look at my old red ones (that are truly red) and see if there's any writing on them. I keep then in the center console as emergency backups, but I may donate one to the cause and open it up. I should be able to measure the wire inside.

I can tell you anecdotally that the brand new 0.3 "sorta brown, sorta tan, sorta salmon" links I have installed run nice and cool. Implication being that they are large enough.

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Actually they started in Brown.  Somehow red got in to the picture and sucked many people in, apparently.  EuroDat had all of the info to the right path in his first post, I see after looking at the supercesion trail.

So, what is MSA doing?  They have the wrong diagram, putting weak links in to high current spots, plus, maybe, they are doubling the area of two to three of the links even if they end up in the right spots.  Fat red, 0.69, for thin brown, 0.33.  Go through Nissan for fusible links.

image.png

image.png

image.png

 

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Just offering some clarity for MSA.  They might, accidentally, be the cause of some of those smoke shows out there.  Should be fixed.

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I had the camera handy, so I took some additional pics. Here's the correct position for the links on the 77-78. This time I took the pic from the angle that everyone likes. As it's shown in the FSM:
P1140591.JPG

And here's a pic that (although it's hard to tell), you can actually see that one of the White/Red wires is larger than the other three. That's the position that gets the largest (black) fusible link. The W/R wire gauge is larger to account for the higher current that circuit can potentially carry. Who knows... Since the blocks are just screwed to the fender well, maybe some of them have been switched around? So if you're looking for a way to definitively determine which location gets the largest fusible link, you can check the wire gauge sizes:
P1140594b.jpg

And here's a pic of what remains of my fusible link labeling. Can't make out any of the color listings. Would be great if a 77 or 78 owner could post a pic of better condition labels, but this is all I got left. I can make out ??L (which I assume would be H-L) and "IGN", but that's it:
P1140600.JPG

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Here is a 1/76 build date 1976.  I just left what was there when I got it.  Cleaned them up and gave them a little extra crimp.  Obviously a driver, not a show car.  I think those are the original caps, they're in good shape too.  With patina.

image.png

image.png

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19 hours ago, Captain Obvious said:

Yeah, I know @wal280z is all dreamy about the fuse replacements (note that I didn't say "upgrade" ) for the stock system. He's that kind of guy. Lives for the bling.  ROFL

Call it what you want.... I've got 2 (well, one now since I used a slot for my headlight relay feed) spare +12V fused feeds that I don't have to tap off the battery. No gremlins and no maintenance. Nothing about this screams 'bling'.

100_5146.JPG

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4 minutes ago, siteunseen said:

Interstate Batteries, bling to my eyes. :beer:🎧🤡

Only bling I have is the GOLD lettering on my Duralast Gold series battery. :victorious:

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2 hours ago, wal280z said:

Call it what you want....  No gremlins and no maintenance. Nothing about this screams 'bling'.

Haha!! Very nice! Next time we're together, well have a fuse-off.

So... Out of curiosity, what value fuses did you use, and what made you choose those values?

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19 hours ago, Mark Maras said:

Bling! None of us even come close to RossiZ. He has chromed hood vents on his 280.

I have a hot rod buddy that lives by this saying... "If it don't go, chrome it".

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On 3/13/2019 at 12:36 AM, Captain Obvious said:

What change? I'm not sure what change you're talking about. The 77 and 78 manuals both look the same as far as the links go.
 

Just reading this now and see I made a typo. I should have went to bed about 30 minutes before that post.

I meant August 1976, or I believe the change was around that point. That would mean there are cars built after August 76 with the 77/78 fusible link layout.

 

 

Screenshot_20190315-224256.jpg

Edited by EuroDat
Typo :(
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16 minutes ago, EuroDat said:

 I should have went to bed about 30 minutes before that post.

I was thinking I was an isolated nut case..... I'm not the only one that does that!!!

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21 hours ago, Captain Obvious said:

Haha!! Very nice! Next time we're together, well have a fuse-off.

So... Out of curiosity, what value fuses did you use, and what made you choose those values?

The brown fusible links were replaced by 30A Maxi-fuses.

Why? Fusible link "D" has the most draw on the right-hand side of the fuse-block inside the cabin. It hasn't blown. I didn't want to start high and end up melting the inside fuse-block.

The alternator output is at an 80A maxi-fuse. My memory is going to the crapper and that crapper is flushed multiple times a day, but, if I recall correctly, I found a internally regulated 65A alternator from a early 80's Maxima in the junkyard. There's a 60A Maxi-fuse, and there's an 80A Maxi-fuse. Which would you choose?

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3 hours ago, EuroDat said:

Just reading this now and see I made a typo. I should have went to bed about 30 minutes before that post.

I meant August 1976, or I believe the change was around that point. That would mean there are cars built after August 76 with the 77/78 fusible link layout.

Haha!!   LOL   That's what I figured. And the August 1976 would be the start of the 77 "model year", so it all makes sense.

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21 hours ago, wal280z said:

The brown fusible links were replaced by 30A Maxi-fuses.

Why? Fusible link "D" has the most draw on the right-hand side of the fuse-block inside the cabin. It hasn't blown. I didn't want to start high and end up melting the inside fuse-block.

The alternator output is at an 80A maxi-fuse. My memory is going to the crapper and that crapper is flushed multiple times a day, but, if I recall correctly, I found a internally regulated 65A alternator from a early 80's Maxima in the junkyard. There's a 60A Maxi-fuse, and there's an 80A Maxi-fuse. Which would you choose?

Fuses and other protective devices are not a field of expertise I've been even grazed by in my travels as an EE. But I can tell you that even though the whole thing sounds so simple and mundane, I highly suspect the experts in the field would be quick to refute that. In other words... I bet the people who really know what they're talking about in this facet of engineering (which isn't me) would be able to debate the finer points of this for hours.

That said... I took a quick look on the web and came to the following conclusions:

1.25 mm sq is approx. the same as 16 ga
0.3  mm sq is approx the same as 22 ga   32 ga

And also with some web searching, it seems that the "general convention" seems to be that the fusible link gauge should be four sizes smaller than the wires they are intended to protect. So, for example, 12 ga. wire should be protected by a 16 ga. fusible link. And 18 ga. wire should be protected by a 22 ga. fusible link.

All that really makes me wonder if that brown 0.3 mm sq link is really really correct. Maybe that red link really was the correct one all along?

Edited by Captain Obvious
Slipped a decimal point

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40 minutes ago, Captain Obvious said:

All that really makes me wonder if that brown 0.3 mm sq link is really really correct. Maybe that red link really was the correct one all along?

Wouldn't you need to know what the smallest gauge is among all of the circuits on that link?

I've wondered about Nissan making a mistake but it seems unlikely that they would repeat it year after year, through various FSM's, as other links change size along the way.  Like from 76 to 77.  They changed a green 0.5 to a brown 0.3.  Somebody had to have done some calculations there.

Maybe the red came from somebody else second-guessing the engineers?  But if 0.3 hasn't been melting, what reason would you have to go to 0.5?  Extra risk for no benefit.

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