Thanks to everybody in this thread.  All of this discussion has solved an ongoing problem for me where I kept slowly toasting the fusible link for the alternator and fuse block (it was brown) whenever the headlights were on and only when the engine was running.  It was driving me crazy until CaptO's picture showed up.  I had been blindly going by MSA's diagram and had placed my black link like their example, putting a brown link on the slow roast. I just went down and switched the links to the proper placements.  Nothing gets hot anymore!  Thanks again!

@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.

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.

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:

My 5/77 is this exact way.

 

And it looks like the factory wire schematic is showing the black link reversed as well (?)

Edited March 13, 20196 yr by rcb280z

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.

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..... ?

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. 

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.

The fat red links are ancient history. Nissan has superseded them to a kind of brown.

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.

 

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