In addition to circuit breakers and fuses, the wiring harness incorporates fusible links to protect the wiring. Links are used rather than a fuse, in wiring circuits that are not normally fused, such as the ignition circuit. Isuzu fusible links are color coded and load circuits to match the color coding of the circuits they protect. Each link is four gauges smaller than the cable it protects, and is marked on the insulation with the gauge size because the insulation makes it appear heavier than it really is. The engine compartment wiring harness has several fusible links. The same size wire with a special hypalon insulation must be used when replacing a fusible link.
On early models the links are located in the at the starter solenoid or near the main battery terminal. Later models have a fuse link compartment on the fenderwell under the hood. Many later models use MAX fuses instead of the old style fusible links. A MAX fuse is really a fusible link in a cartridge which looks like a fuse (but with a very high ampere rating). The MAX fuses are usually found near the battery or main relay case.
See Figures 1, 2, 3, 4, 5 and 6
Plug in fusible link or MAX fuses simply plug into the fuse link box or the relay center. Some models may use short fusible links with spade connectors on each end. The spade connector type simply unplug also. Care must be taken on the wire design to replace them with the same ampere rating fuse link or fire could result.Wire Type Fusible Links
- Determine which circuit is damaged, its location and the cause of the open fuse link. If the damaged fuse 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 fuse link from the wiring harness and discard it. If the fuse 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 fuse link and butt connectors for attaching the fuse link to the harness.
To repair any fuse link in a 3-link group with one feed:
- After cutting the open link out of the harness, cut each of the remaining undamaged fuse links close to the feed wire weld.
- Strip approximately 1 / 2 in. (13mm) of insulation from the detached ends of the two good fuse links, Then insert two wire ends into one end of a butt connector and carefully push one stripped end of the replacement fuse link into the same end of the butt connector and crimp all three firmly together.
Care must be taken when fitting the three fuse 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 cutter, etc. will not apply the proper crimp to retain the wires and withstand a pull test.
- To replace any fuse 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 fuse link to the stripped wire ends with two proper size butt connectors. Solder the connectors and wires and insulate with tape.
- To repair any fuse link which has an eyelet terminal on one end such as the charging circuit, cut off the open fuse link behind the weld, strip approximately 1 / 2 in. (13mm) of insulation from the cut end and attach the appropriate new eyelet fuse 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 fuse link. The resistor wire is generally longer and has print stating, Resistor-don't cut or splice''.
When attaching a single No. 16, 17, 18 or 20 gauge fuse link to a heavy gauge wire, always double the stripped wire end of the fuse link before inserting and crimping it into the butt connector for positive wire retention.