Fusible link?

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Pawned

Pawned

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I have a 71 Duster with a 318 V8 in it. When I first started working on the electrical system the fusible link blew. Lots of smoke and stink.
It is connected to bulkhead connector 'J', which directly connects the alternator to the ammeter.

As I had not idea where to get a replacement part, I replaced the wire fuse with an actual fuse. I had no idea what the amperage was/is so I asked the guy at the parts store. He said that he would think 15 or 20 amp fuses would be enough. It wasn't.
I put in a 30amp fuse, which has blown many times, usually my own fault. But a couple times, today being one of them, the fuse will pop in the middle of the road at 40 mph.
I have been working on the electrical the last couple days, so maybe I weakened it.
My question is, What Ampere rating should the fusible link be???
I am hesitant to go over 30 without some verification.

Thank you in advance for any information you can provide

Ed
 
A fuse link is vastly different from a fuse, in that it needs to be able to handle a large overload. The thing is, unless you have done the "ammeter bypass" ALL the current used by the car goes through that link except for starter current. This includes the output of the alternator, so if you happen to have a 55 - 60 amp alternator, and the battery is a little low, that fuse link will "see" as much as the alternator can put out until the battery starts to "come up.

I've never known, really what the damn things are actually supposed to be rated at. The fact is that the earlier cars (at least 70 / earlier) were very UNDER protected, an example and a story

In the early 70s not long after buying my favorite car, a 70 440-6 RR which was limelight, some girl a$$holed it while I was stopped in traffic. She was "window shopping." I digress

I got a loaner BTS (beat - to - .......) Valiant from McCune Chrysler Plymouth in National City.........don't EVER do business with them............and one cold morning in San Diego, NAS Miramar, the alternator shorted.

The entire underhood harness welded itself into a flaming, smoking, stinking worm of wrinkled carbonized plastic, and then........................ the fuse link blew.
 
A better name for the link would have been Safety Link. It doesn't compare to a fuse at all really. Fuse in its name causes confusion or misinterpretation at least.
A wire is rated/sized to carry a desired amount of current without overheating. A safety link in that wire is typically 2 wire gauge sizes smaller than the wire its protecting ( there is some deception in that too ) . These safety links are always placed outside the cabin to prevent burnin' the beans ( beings ).
So what actual fuse contains a link that compares to the multi strand wire in a safety link ?, none, not even the maxi fuses.
I'm not going to comment on safety link construction other than to say its not the same copper as the wire attached to it. Why that is gets far too complicated for most of us.
I wont add comments on your working on the electrical while hot either. You have already found the faults in that.
There are ways to isolate, diagnose, and repair individual circuits, but nobody knows everything. That's why a dealership service dpt. will have a engine specialist, a trans' specialist, electrical specialist, etc..
Good luck with it.
 
Morning, I agree with RedFish and 67dart273 on their advice. It was explained to me by a very reputable man that has been doing wiring repairs on muscle cars for years plus he has is own business. Anyway, the fuseable link is a safety device like a circuit breaker in your house, you don't want to over rate the safety link, that takes away the safety protection in that circuit which in turn puts the weak spot else where like the bulkhead connector.

The attached pic's show before and after photo's of the wire coming off the starter relay to the bulkhead. The red wire was 12g changed to 10g. The grey wire is the fuseable link. Note it is smaller than a 10g wire also the fuseable link (wire) is mounted directly off the starter relay. You want the protection of the fuseable link (wire) as close to the power source as possible. That prevents any damage further down the circuit say inside the car. My understanding on the size of the fuseable link (wire) should be 2 to 4 wire sizes smaller than the wire you are running.

Good luck. Bink
 

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I went to the parts store to buy the fusible link. They had no idea what it should be. They had different color wires but no amp rating on the packages.
My intention was to buy new link, but could not find anyone that had any idea who,what,or where to find it.
So I went to the fuse instead of not having any protection.
If I can find the proper fusible link, I will replace the fuse with it
 
At Napa it's called primary wire. I han #8 from alternator wih #12 fuseable link to the starter relay. Solder and shrink vrap connection.
 
Mogre said:
At Napa it's called primary wire. I han #8 from alternator wih #12 fuseable link to the starter relay. Solder and shrink vrap connection.
Click to expand...

If that's true, and I don't believe it is so, that's a VERY poor name. "Primary wire" is a term usually used for just what it says.......primary wiring. As in, directly off the battery. I could call the alternator charge line, and the red ammeter feed to be primary, as well as the splice and wire feeding the headlamps and ignition switch, and hot fuse box feed.

According to this it's called "fusible link" or "wire fusible link"

http://www.napaonline.com/Catalog/R...&Nty=1&Dn=0&D=Wire+Fusible+Link&Dk=1&Dp=3&N=0
 
67Dart273 said:
According to this it's called "fusible link" or "wire fusible link"

http://www.napaonline.com/Catalog/R...&Nty=1&Dn=0&D=Wire+Fusible+Link&Dk=1&Dp=3&N=0
Click to expand...

Something very interesting about these links, they all have a limited lifetime warranty. If you look at the warranty, it is for a spark plug wire.
The fusible link I assume is guaranteed until it is needed, in other words until it blows.
Which one is for my car the 14, 16, or 18. It has no specs so it is a crap shoot
 
foxmopar585 said:
THE big ? what blew the link check the amp gauge insolater go bad on dash panel
Click to expand...

I know why it blew, but it was 6 months ago and I do not remember.
This is what I wrote in the car's journal. July 24th
[FONT=Arial, sans-serif]Had an electrical problem when I set the dash cluster back in place and then reconnect the battery. It caused a burnt out a fusible link, There is a whole lot of smoke that make you think you set you car on fire. In reality it did what it was suppose to do.[/FONT]

I have since fixed that problem with the the dash cluster until last night, the voltage regulator in the dash seems to be malfunctioning[FONT=Arial, sans-serif]. [/FONT]
I just now want to get the proper fusible link to put it back to original.

And we are not even discussing the electrical fire in car
 
foxmopar585 said:
sorry just tryed to help
Click to expand...

Please do not be sorry, I appreciate the help no matter what it is. What I get upset about when people repeat the same thing over and over.

I know that you were trying to help. Sometimes I come up short with people, but that is one of my character traits
 
Oklacarcollecto said:
I was taught the fusible link should be 2 wire sizes smaller than the wire it is hooked to and never longer than 9" long.
Click to expand...

If I remember correctly it was not longer than 9" and the size when I noticed it was burnt to hell

For the most part, I am using 14awg wire If anything I oversize my wires
 
Mogre said:
Just to clarify, napa #785856 12ga 10' fusible link primary wire.
Click to expand...

Sorry to resurrect this old thread, but I'm literally pulling my hair out here as I can't find fusible link anywhere.

The stealership wants an arm and a leg for fusible link (1+ weeks to have it shipped in), and Mogre is saying primary wire can be used as a fusible link (remember we're in Canada and napaonline.com is different from our napacanada.com site). Anyways I took a look at the primary wire Mogre suggested at NAPA and it definitely doesn't look like fusible link, nor does it have any markings on it to indicate it is fusible link. The outer jacket on the wire looks like it would burn up instead of containing the short should something happen too so I'm pretty leery on using this.

Any real alternatives? Pretty sick of researching this (5+ hours now) with no clean alternative or solution.
 
Hmmm i had the same issue when i redid my guage cluster, the ammeter gauge shorted to the gauge cluster which smoked it, i think i found one at carquest auto parts but decided not to use it so i wired in a 30 amp fuse and havent had any problems.
 
Hi,

Most Chrysler products of the late 60's, early 70's used a 16 gauge fusible link, they are usually color coded blue. Aftermarket links may be another color but the important issue is you want a 16 gauge link.

You want a device that is going to hold up to the maximum electrical load of the car and the maximum alternator output. A 30 amp fuse is a bit on the light side to do this. Others may agree or disagree but I favor a 50 or 60 amp Maxi-fuse in a system with a stock alternator. This is roughly equivalent to the old 16 gauge link but has more controlled and defined characteristics as to when it will melt. Most auto makers gave up on the fusible links and went to Maxi-Fuses by the late 80's. They are available at any auto parts store and even large hardware stores. I like to mount them in a quality holder like a NAPA P/N 784482.

DO NOT use regular primary wire to replace a fusible link, especially something as large as 12 gauge. If you do and something goes wrong you will have a fire for sure.
 
saapbaad said:
Sorry to resurrect this old thread, but I'm literally pulling my hair out here as I can't find fusible link anywhere.

The stealership wants an arm and a leg for fusible link (1+ weeks to have it shipped in), and Mogre is saying primary wire can be used as a fusible link (remember we're in Canada and napaonline.com is different from our napacanada.com site). Anyways I took a look at the primary wire Mogre suggested at NAPA and it definitely doesn't look like fusible link, nor does it have any markings on it to indicate it is fusible link. The outer jacket on the wire looks like it would burn up instead of containing the short should something happen too so I'm pretty leery on using this.

Any real alternatives? Pretty sick of researching this (5+ hours now) with no clean alternative or solution.
Click to expand...


What year is your duster, mine is a 73 and is located about 6" from the bulkhead connector on the firewall side.
 
sireland67 said:
What year is your duster, mine is a 73 and is located about 6" from the bulkhead connector on the firewall side.
Click to expand...

1974 but the motor is a 1972 340.

Either way, I was working on the ammeter bypass today and the wiring harness has melted wire jackets (on the POWER runs!!) and was hacked to **** by the previous owner.. I'm surprised this hasn't burnt to the ground yet.

Ordering a Ron Francis kit tonight/tomorrow once I get all the specifics sorted out and won't need to worry about fusible links/replacements.
 
I cut mine out and replaced it with a 30 amp self resetting circuit breaker.
The breaker acts a bit like the fusible link as in it doesn't trip immediately but will if things get hard shorted.
It will also trip if there is enough of a short that could burn wires, but then it automatically resets itself.
This gives you a fair warning to disconnect the battery and find out what is going on, but it has never tripped (even when the battery was a little low) because like I said, it can handle higher loads than 30 amps for a short time.

If for example all your power goes off, comes back on in 5 seconds and goes back off again you have a short capable of burning 12 ga wires and you can disconnect the battery and find out where the problem is.
If you reconnect the battery and have not solved the problem, then it'll just trip again.

The people who insist on replacing it with a new fusable link are just stuck with what it is and does, as well as with all the mystery and replacement issue's.
What happens if it burns up far from help somewhere?
 
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