The fusible link is a short length of special, Hypalon (high temperature) insulated wire, integral with the engine compartment wiring harness, and should not be confused with standard wire. It is several wire gauges smaller than the circuit which it protects. Under no circumstances should a fusible link replacement repair be made using a length of standard wire cut from bulk stock or from another wiring harness.
When a fusible link blows it is very important to find out the cause. Do not just replace the link to correct the problem. The fusible links are placed in the system for protection against dead shorts to ground.
In some instances the link may be blown and it will not show through the insulation. Check the entire length of the fusible wire when the link is suspected of failure.
To repair any blown fusible link use the following procedure:
- Determine which circuit is damaged, its location and the cause of the open fusible link. If the damaged link is one of three fed by a common No. 10 or 12 gauge feed wire, determine the specific affected circuit.
- Disconnect the negative battery cable.
- Cut the damaged fusible link from the wiring harness and discard it. If the link is one of three circuits fed by a single feed wire, cut it out of the harness at each splice end and discard it.
- Identify and procure the proper fusible link and butt connectors for attaching the link to the harness.
Care must be taken when fitting the three fusible links into the butt connector as the internal diameter is a snug fit for three wires. Make sure to use a proper crimping tool. Pliers, side cutters, etc. will not apply the proper crimp to retain the wires and withstand a pull test.
To repair any fusible link in a 3-link group with one feed:
- After cutting the open link out of the harness, cut each of the remaining undamaged fusible links close to the feed wire weld.
- Strip approximately 1 / 2 in. (13mm) of insulation from the detached ends of the two good links. Then, insert two wire ends into one end of a butt connector and carefully push one stripped end of the replacement fusible link into the same end of the butt connector and crimp all three firmly together.
- After crimping the butt connector to the three fusible links, cut the weld portion from the feed wire and strip approximately 1 / 2 in. (13mm) of insulation from the cut end. Insert the stripped end into the open end of the butt connector and crimp very firmly.
- To attach the remaining end of the replacement fusible link, strip approximately 1 / 2 in. (13mm) of insulation from the wire end of the circuit from which the blown link was removed, and firmly crimp a butt connector or equivalent to the stripped wire. Then, insert the end of the replacement link into the other end of the butt connector and crimp firmly.
- Using rosin core solder with a consistency of 60 percent tin and 40 percent lead, solder the connectors and the wires at the repairs and insulate with electrical tape.
- To replace any fusible link on a single circuit in a harness, cut out the damaged portion, strip approximately 1 / 2 in. (13mm) of insulation from the two wire ends and attach the appropriate replacement link to the stripped wire ends with two proper size butt connectors. Solder the connectors and wires, then insulate with tape.
- To repair any fusible link which has an eyelet terminal on one end, such as the charging circuit, cut off the open fusible link behind the weld, strip approximately 1 / 2 in. (13mm) of insulation from the cut end and attach the appropriate new eyelet fusible link to the cut stripped wire with an appropriate size butt connector. Solder the connectors and wires at the repair and insulate with tape.
- Connect the negative battery cable to the battery and test the system for proper operation.
Do not mistake a resistor wire for a fusible link. The resistor wire is generally longer and has print stating, "Resistor: don't cut or splice.'' DO NOT replace blown fusible links with standard wire. Use only fusible type wire with hypalon insulation or damage to the electrical system could occur. Make sure the correct gauge of wiring is used.