Fusible link gone

Scotty4

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Installed my gauges and decided to tap off the unused roof marker lights wire. I removed some insulation, soldered on two 18ga wires coming from the pod and another on the dash and then grounded all gauges together on a good chassis ground. Initially my first test was good until I got everything back together and got no lights. Very dim dome light. Decided to check links and found the black with orange stripe link blown.

I had put the key in the ignition and didn't even get the door buzzer and it can't turn over. Safe to assume the link was on its way out and the extra draw killed it?

Best replacement? Any help would be great, wanted to do a dump run tomorrow!!!

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franklin2

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Replace the fusible link with another. A better place to power the gauge lighting is from a blue/red dash light wire. This wire has it's own fuse in the fuse box, and it also will brighten and dim with the dimmer on the headlight switch, making your new gauges adjust with the rest of the dash lights.
 

Scotty4

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Replace the fusible link with another. A better place to power the gauge lighting is from a blue/red dash light wire. This wire has it's own fuse in the fuse box, and it also will brighten and dim with the dimmer on the headlight switch, making your new gauges adjust with the rest of the dash lights.
Alright, I'll tap into that one. I did not see any links at the store, online thing?
 

Scotty4

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Looks like to 300 O (Orange) fusible link supplying ignition and headlight switch. Is the size labeled on the wire connectors or does that mean 300 amp?

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Kizer

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I've replaced it on almost every truck in the remuda. I use these:

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It's a 40 amp fuse ... comes with comes with 8 gauge (I believe) pig tales about 6" long ... about $11 at O'Reilly. ((EDIT: Part # MAH1 Line: (Lit) made by Littlefuse))
 

hacked89

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Looks like to 300 O (Orange) fusible link supplying ignition and headlight switch. Is the size labeled on the wire connectors or does that mean 300 amp?

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Edit: I didn't read Kizer while typing this up.. Go theory haha

What's up Scotty. I do most of my work off fundemental theory and not IDI specific knowledge, cause this is my first idi teardown and restore.. But I'll give what I think if no one chimes in.
Generally fundementals can get you through any vehicle.

Without the factory color code chart it's not that straight forward because a fusable link is a function of its size and length, like most electrical.

But generally if you look at a diagram and want replace the fusable link with another fusable like we know that you can only run X current over X gauge wire.

You can take the gauge of the wire of the circuit and do a fusable link (4) less than the circuit. You have a 16 gauge circuit, which you would than say a 20 gauge fusable link.
On Chrysler ignition circuits in the same time period their 16 gauge ignition circuit, would use an Orange fusable link which was 40amps.

Sounds familiar?
Maybe one of the guys that were IDI mechanics years ago could confirm but you get the idea.

Also, some people like fusable links some people don't. IMO I have read that the fusable links in the 80s saved about 35 to 50 cents a vehicle which added up quick. They are suppose to be lifetime which is why the people that advocate replacing them with another fusable like them.

On my stuff, I don't like anything that fail burns. I insert either single inline maxi fuse or put all fusable links to a breakout fuse box.


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franklin2

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Yes, that is the one. It should be all over the dash, every light in the dash that lights up at night is driven by that wire.

I like fusible links. The are small compact and can be easily weatherproofed. Maxi fuses are ok, but are large and clunky and you need room to mount them. Whatever you prefer.

The fusible link is that large rubber piece in the wire, and it should have written on it what gauge it is. Like someone else mentioned, it's just a undersized piece of wire that gives out before the rest of the harness melts. What is special about it is it has special insulation around it that will not catch fire when it burns out. The store should have a roll of fusible link wire,, they cut a short piece off for you and you solder it in place in the harness.
 

IDIBRONCO

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Franklin2, here's a question related to this. I'm wanting to install some more gauges and I want to power them off of this blue/red wire. If I used it to trigger a relay (instead of actually powering the gauge lights off of it) would it still dim with the headlight switch? That would be nice, but isn't really necessary to me. I run the dash lights as bright as they will go as it is.
 

Scotty4

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@IDIBRONCO I'm guessing no. Since a relay is a switch with power to it being switched by the red/blue, it would just open or close as you turn on and off the dash lights. I would also assume the dimming function would cause constant switching of the relay.

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hacked89

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Franklin2, here's a question related to this. I'm wanting to install some more gauges and I want to power them off of this blue/red wire. If I used it to trigger a relay (instead of actually powering the gauge lights off of it) would it still dim with the headlight switch? That would be nice, but isn't really necessary to me. I run the dash lights as bright as they will go as it is.
what Scotty said. It's a variable resistor creating a voltage drop. When it's dim would probably be flapping the relay. Also.. What were your thoughts on why you wanted to use a relay?
There isn't large amperage differential in what you described, shouldnt be an issue for the switch to put all the gauges on the dimmer circuit.

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Selahdoor

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Yes, that is the one. It should be all over the dash, every light in the dash that lights up at night is driven by that wire.

I like fusible links. The are small compact and can be easily weatherproofed. Maxi fuses are ok, but are large and clunky and you need room to mount them. Whatever you prefer.

The fusible link is that large rubber piece in the wire, and it should have written on it what gauge it is. Like someone else mentioned, it's just a undersized piece of wire that gives out before the rest of the harness melts. What is special about it is it has special insulation around it that will not catch fire when it burns out. The store should have a roll of fusible link wire,, they cut a short piece off for you and you solder it in place in the harness.
Franklin,

I thought the entire wire was the fusible link, It's just a smaller gauge wire that will burn before your regular wire will.

And that the rubber piece is there just to identify it as such.

If that is not the case, why does that entire wire burn up, when the fusible link goes out?
 

Scotty4

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Franklin,

I thought the entire wire was the fusible link, It's just a smaller gauge wire that will burn before your regular wire will.

And that the rubber piece is there just to identify it as such.

If that is not the case, why does that entire wire burn up, when the fusible link goes out?
Looking at all the wiring tonight, each link has an eye on one end and a length of fusible wire which ends at the rubber cover where I assume its soldered and this denotes the size. The one I have says 16 GA. There is another one with a blue 20 GA for the gp solenoid on the black/pink wire.

Looks like the same company that made the diode I requested about previously also made all the links for them. At least the nice rubber covers.

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