Fusible Link

furyfever

furyfever

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What size Amperage fusible link is supposed to be in our C's...more precisely in a 1968 Plymouth Fury III w/ 383? I inadvertently burned it out yesterday changing my alternator out. Stupid... :BangHead: I verified that this is the problem by cutting into it...pigtail on middle bulkhead connector on firewall driver side. It's labeled with a yellow rubber tag "fusible link" on both sides but no value is typed on it. I replaced it temporarily with a jumper wire for now and verified I have power to everything but will not drive it or leave power to the car until I get the proper size fusible link soldered back in place. Advance and or Autozone have them but need to know Amps. so I can pick one up.

Thanks, Bob
 
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furyfever said:
What size Amperage fusible link is supposed to be in our C's...more precisely in a 1968 Plymouth Fury III w/ 383? I inadvertently burned it out yesterday changing my alternator out. Stupid... :BangHead: I verified that this is the problem by cutting into it...pigtail on top bulkhead connector on firewall driver side. It's labeled with a yellow rubber tag "fusible link" on both sides but no value is typed on it. I replaced it temporarily with a jumper wire for now and verified I have power to everything but will not drive it or leave power to the car until I get the proper size fusible link soldered back in place. Advance and or Autozone have them but need to know Amps. so I can pick one up.

Thanks, Bob
Click to expand...
I think 40amp is good but 60amp is max after that meltdown comes.
Skip amp meter. That damn thing has burned more Mopar than nothing and sometimes has killed people also.
 
Just happened to have a 68 Plymouth FSM handy, so I looked it up.

The wire size for fusible link for your car is #16. Fusible links are usually listed by wire size, so if that shouldn't be a problem.
 
FYI, usually fusible links are 4 sizes smaller than the wire size for the rest of the circuit. It just caught my eye that Chrysler decided to use #16 Fusible link on a circuit that has #10 wiring. So for some reason, they decided to make it a little smaller.

Info is from page 8-125 in your FSM.
 
Slantsix said:
Skip amp meter. That damn thing has burned more Mopar than nothing and sometimes has killed people also.
Click to expand...

Where do I find info how to correctly do this? Is there a sticky? Sounds like a very important thing to do.
 
Big_John said:
Just happened to have a 68 Plymouth FSM handy, so I looked it up.

The wire size for fusible link for your car is #16. Fusible links are usually listed by wire size, so if that shouldn't be a problem.
Click to expand...

I'll concede that if he has a #10 wire, w a 40 amp alternator, #16 would be appropriate and Mopar did some stuff like that back then. My '66 Newport had #12 on a #8 AWG feed. I went with this, and re-routed my alternator DIRECT to the battery post, after making a 6 inch length of #12 awg fusible link, soldering to a #12 to #8 splicer and using a 1/4" ring terminal for the alternator post. I run a 60 amp alternator, so #8 awg at 12 VDC at a length of ~ 30 in is reasonable, and has worked very well after my wiring fire this past April. I advise anyone running a 60 amp alternator to use at least the same ampacity I have, which, surprise, surprise, happens to be specified in the FSM for my ride. I saw at the junk yard a '68 with the #16 AWG link too, so I know they did it, but I don't recommend it.
 
furyfever said:
... until I get the proper size fusible link soldered back in place.
Click to expand...

Also... DO NOT SOLDER... the solder will wick into the wire and raise the amperage it opens at... may as well not run a link at all if that happens...
 
Thanks guys...so the consensus seems to be that I need a #16 fusible link and NOT to solder in place so I guess I'll have to use heat-shrinkable crimps that are waterproof. When I called Advance Auto, that's where I got the idea that they were sold by Amp rating, so obviously that's most likely NOT where I'll probably be getting a new fusible link. Since it's a #16...and not a fuse, is it just a #16 gauge (braided) wire? That's what it looked like when I cut into it...and it did appear to have solder at both ends.

Rexus....nice job on your fusible link but it doesn't look like mine at all. I should have taken a photo before I cut into it. Mine's one simple short wire (pigtail) from middle bulkhead connector to a thick red wire coming out of harness at top of firewall.
 
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NAPA should have a fusible link if you can't find it at the other stores and it's not just regular wire.
 
Dorman Conduct-Tite 85627 - Fusible Link Wire | O'Reilly Auto Parts

Hey Guys, If I get one of these #85627 Dorman Fusible Links, I can solder this one in place correct?...(and use heat shrink tube on both ends to insulate) because it appears there's plain old wire on both ends....correct? Reason: I have inspected what I have closely and will not be able to get either pin out...of the bulkhead connector at the firewall or the single pin connector going to the thick red wire.

Bob
 
No
85627-007.jpg

Butt splice only. Get the ones that heat shrink, they keep moisture out and help support the splice... solder is never to be used on this wire, also as mentioned before don't make it too short.
 
cantflip said:
No
85627-007.jpg

Butt splice only. Get the ones that heat shrink, they keep moisture out and help support the splice... solder is never to be used on this wire, also as mentioned before don't make it too short.
Click to expand...

Referring to the photo above, the length of the actual fusible link is buried in the center of the length of this wire...correct? Probably about where the rubber tag is...I'd estimate the original fusible link length that burned up was only about 1" long (see photo below). I cut it out so I know...and BTW I saw solder in there. This whole wire (above) is probably 7" long. Can you please explain why solder can't connect wire to wire especially if the fusible link is ~ 3" away on both sides? Would that solder that's 3" away still change the resistance of the fusible link? If that's so, wouldn't any connection along the length of this wire change the resistance of the fusible link? Wouldn't any wire harness modification at all through the years change the resistance as well? In no way am I trying to argue...just would like to understand. Thanks...



Here's the situation...If worse comes to worse I probably could find another connector/pin to the thick red wire...although I don't own the pin pusher tool for that connector. As far as the bulkhead connector side...forget it. That pin is not coming out...and it's scary how short of "a stub" of wire I have to work with. I've got to make sure I know what I'm doing because I can't afford to lose anymore wire on that end. I am tempted to neatly solder a little extra wire/heatshrink tube it on that end BEFORE I crimp the fusible link in. Then comes the decision on whether to cut down the fusible link wire when I get it. Is the length of the whole wire not critical...but only the length of the fusible link itself? There seems to be a lot of unknowns here....

Bob
 
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If you do not have the tools (or knowledge; no dig intended) to properly make the repair, I would take it to someone who does. Also, I believe you have Fusible Link wire coming out of the Bulkhead. There would not be a piece of Fusible Link pieced in between two wires like that; at least not from the factory. It should terminate somewhere with a proper connector (Bulkhead). The Fusible Link is a vital part of the wiring and if you repair it incorrectly, there's a good chance, at some point, you could have an electrical fire. Do you have a wiring diagram for your car? It would be worth its weight in gold right about now.
 
This is what your fusible link should look like, minus the parts tag. Notice there are two ends that are crimped on. One goes in the bulkhead and one is clipped to the other wire.

s-l1600.jpg
 
You are not seeing solder. What you are seeing is the wire itself. It has probably melted a little from you shorting the wire.

The best way to do this is to replace the wire using the proper end terminals that clip into the bulkhead connector and to the insulator on the end that clips to the wire. Those terminals are a little hard to find and your local Autozone probably won't have them.

The next best way is to cut the existing wire off and splice into the old fusible link wire. Cut the old wire so there is maybe an inch or so sticking out of the insulators and use butt connectors as Cantflip described.

Don't solder.

The fusible link needs to be approximately the same length as the old one when you are all done. Too short and you don't have the protection you should. Too long and you've added too much resistance and may end up burning the wire up again.

I hope that clears it up for you.
 
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