I am retaping my wire harness and ran across these weird looking black rubber things wrapped around some of the wires, arournd the voltage regulator and horn relay. Some of the wires have broken off from the end of the rubber things. I think these are called fusible links.

My question is, do these things (fusible links)serve any major purpose? I would like to take the rubber things off and splice the two wires together instead but don't know if doing this will do any harm to my electrical system.

Does anyone have any information or suggestions about these little rubber things on the wires?

Kent.

Kent. Fusible links are meant to blow before the wire can get into trouble when the current rises. Physically it is a piece of wire of a higher gauge number. It is not reparable, but with the right piece of wire they can be replaced. Their length sould be limited to some 2 inch max. You may always replace them by adding maxi fuses.

Hope this helps.

Rob

Kent,
Most auto parts stores sell fuseable links. They are sized by the wire size that they are protecting. If the wire is 12 ga then you get a 12 ga fuseable link. I would not recommend removing them. They protect the main wires from the battery to the fuse block. If you had a short circuit somewhere you could turn your pride and joy into a carbecue real quick :(

"carbecue"

that's funny (but true)
:D

Originally posted by BillK:
They are sized by the wire size that they are protecting. If the wire is 12 ga then you get a 12 ga fuseable link.Bill
Maybe a typo or just the way this reads. Fusible links are normally 2 wire sizes smaller than the wire gage they protect. As you know the fusible link should burn open before any damage occurs to the circuit wire.

I'll chime in.

I believe it isn't as simple as using a short piece of wire two sizes smaller than the rest of the wire.

Fusable links are made of a special material so as to sever the electrical connection without causing a fire.

I never really understood why manufacturers used fusable links rather than a comperable fuse, but, whatever.

I had one blow on my Mazda pickup. The book indicated it was rated for 90 amps. I figured I was in for some troubleshooting, so rather than buy a bunch of fusable links, I soldered three spade fuse holders together in parallel, and used three 30 amp fuses. Of course I blew several sets of three, but it was cheaper in the long run until I found the problem.

Dave

According to the service manual a link is normally 4 ga sizes smaller than the circuit it's protecting.

The links are:

</font> Pigtail lead at battery positive cable, 14 gauge (brown), protecting the 10 ga. battery charging circuit</font> 16 ga (black) link located at the horn relay protecting all unfused wiring 12 ga or larger.</font> The gen warning light and field circuitry are protected by a 20 ga (orange) link installed in the battery feed to the voltage regulator #3 terminal wire</font> The amp ga circuit is protected by two 20 ga (orange) links, one at the horn relary common terminal and another from the source at the junction block on core support.</font>

Originally posted by rthlc:
According to the service manual a link is normally 4 ga sizes smaller than the circuit it's protecting.

The links are:

</font> Pigtail lead at battery positive cable, 14 gauge (brown), protecting the 10 ga. battery charging circuit</font> 16 ga (black) link located at the horn relay protecting all unfused wiring 12 ga or larger.</font> The gen warning light and field circuitry are protected by a 20 ga (orange) link installed in the battery feed to the voltage regulator #3 terminal wire</font> The amp ga circuit is protected by two 20 ga (orange) links, one at the horn relary common terminal and another from the source at the junction block on core support.</font>I stand corrected, you are right. In the American Wire Gage standard (AWG) there are the odd number size wires such as #7, #9, #11, etc. These are not common wire sizes that can be purchased. I forget that the numbers exist. When I refer to increasing or decreasing a wire to the next size or sizes, I skip the odd numbers. Just an old habit.

If I hadn't just been reading that section of my manual to splice in my gauge console I would never have even noticed.

I guess the color codes are universal, at least for American made cars because when I bought some a couple weeks ago I noticed the colors were the same for Ford and Mopar links as well.

I don't want to speak for Bill but beleive what he said is correct. When you are replacing a fusable link on a 12ga wire you buy the link for the wire size. The rating on the link is the wire size it will protect. The rest of you are also correct though as the internals of the link will be rated lower than the wire it protects.

John,
As Dennis said...if I call my parts supplier and I need a fuseable link to protect a 12ga wire...I order a "number 12" link. I do not have a clue as to the size of the internal wire in the link, just know that is how they are numbered, at least the brand I have been getting. It might be different from different manufacturers ?

Fusable links should be 4 gauges smaller than the wire it is protecting, i.e., 10 ga wire will need a 14 ga fusable link about 5-6" long. Now this is for bulk fusable link that you make up and cut yourself. Store package links usually are marked for GM and some type of rating, amps, wire size or location (i.e., starter, volt reg, etc.). The insulation on the fusable link is not the same as on regular wire, it is designed not to burn thru and cause a fire when the link fails (it will still cause some smoke). The advantage of using links over fuses is that they are hard crimped or soldered into the wire it is protecting. Fuses have a nasty habit of corroding where they make contact in the socket, increasing resistance and current, causing a mysterious blown fuse. A neat trick to use, and the credit for this one goes to Mark Hamilton at M.A.D. Electrical, is to crimp or solder an extra fuse link side by side with the working link, and only attaching it on one end, this will give you a ready spare, already in place, just attach the loose end when you need it graemlins/beers.gif .