I searched this and I cant seem to find any clear answers. The fusible link for the ignition system on an 89 302 is on a yellow wire directly by the starter relay, correct? I cant find the fusible link. thanks :itsatrap
A, F, G, L, M, N, P & W Location in Engine Bay Diagram in a 90 5.0 & 5.8 Page 2
Source: by Seattle FSB (SeattleFSB) at https://www.supermotors.net/registry/media/860013
Bad Fusible Link pic & depiction; "...most fusible links have melted/charred insulation when they burn out..."
Fusible Link J;
Location pics in an 85 & 89 (between the starter relay and alternator)"...the first two pics are of an 89 5.0. because of the loom i wasn't able to trace the wires...The second pic is at the starter relay to show you a fusible link wire (the green wire in my fingers you can see at the eyelet there is a black plastic block). the third pic is of my 85. i think that big block is another style fusible link ford used on older stuff (but im not sure)..."
Source: by shift1313 (Matt) at Ford Bronco Zone Forums http://broncozone.com/topic/15953-no-spark/page-2?&
I am having trouble getting my 85 bronco to start. found a Lt. Blue Fusible link coming from my fuel pump relay burned out, no melted insulation, just no wiring for 1/2", states "fusible link 20 GA." can Not find a fusible link to replace but found 18GA. fusible link, just need to know where link connects to, Ground or Hot??
Fusible Link S, Blue, 20 gauge to the fuel pump relay (hot side)
Source: by Ryan M
Location pics in an 85 & 89 (between the starter relay and alternator)"...the first two pics are of an 89 5.0. because of the loom i wasnt able to trace the wires...The second pic is at the starter relay to show you a fusible link wire (the green wire in my fingers you can see at the eyelet there is a black plastic block). the third pic is of my 85. i think that big block is another style fusible link ford used on older stuff (but im not sure)..."
Source: by shift1313 (Matt) @ https://broncozone.com/topic/15953-no-spark/
The fuse 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 that it protects. May need to remove black/red cable from starter relay to alternator B terminal to measure gauge.
CAUTION: Under no circumstances should a fuse link replacement repair be made using a length of standard wire cut from bulk stock or from another wiring harness.
The higher melting temperature properties and additional thickness of the Hypalon insulation will usually allow the undersized internal fuse wire to melt and disintegrate within the Hypalon casing with little damage to the high temperature insulation other than discoloration or bubbling of the insulation surface. In extreme cases of excessive circuit current, the insulation may separate after the fuse wire has disintegrated. However, the bare wire will seldom be exposed. When it becomes difficult to determine if the fuse link is burned open, perform a continuity test. When heavy current flows, such as when a booster battery is connected incorrectly or when a short to ground occurs in the wiring harness, the fuse link burns out and protects the generator or wiring.
If it becomes necessary to replace a fuse link in a wiring assembly, make sure the replacement fuse link is a duplicate of the one removed with respect to gauge, length and insulation. Original Ford replacement fuse links have insulation that is flameproof. Do not fabricate a fuse link from ordinary wire because the insulation may not be flameproof.
If a circuit protected by a fusible link becomes inoperative, inspect for a blown fuse link. If the fuse link wire insulation is burned or opened, disconnect the feed wire part of the wiring and cut out the damaged portion as close as possible behind the splice in the harness. If the damaged fuse link is between two splices (weld points in the harness), cut out the damaged portion as close as possible to the weld points.
NOTE: 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."
NOTE: When attaching a single No. 16, 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.
NOTE: Always attempt to make replacement link as close in length as original damaged link.
To service any blown fuse link use the following procedure:
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 battery ground 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.
Strip wires 7.6mm (0.3 inch) and insert into proper gauge wire connector.
Crimp the wires with Wire Fitting Crimping Tool T67S-17018-A and heat splice insulation until tubing shrinks and adhesive flows from each end of connector.
To service a two-link group when only one link has blown and other link is not damaged:
Cut out blown link (two places).
Position correct eyelet type service fusible link, bare butt connector and insulation tubing.
Crimp connector and heat insulation until tubing shrinks and adhesive flows from each end of connector.
To replace any fuse link on a single circuit in a harness, cut out the damaged portion, strip approximately 12.7mm (1/2 inch) 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.
If the damaged fuse link is between two splices (weld points in the harness), cut out the damaged portion as close to the weld points as possible.
To repair any fuse link that has an eyelet terminal on one end such as the charging circuit, cut off the open fuse link behind the weld, strip approximately 12.7mm (1/2 inch) 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.
Connect negative battery cable to battery and test the system for proper operation.
Try a local mom and pop store for the link wire. They usually have a catalog going back to 1914. Chain stores may have a data base but i would rather see it in hard copy.