AbleThought Posted May 14, 2016 Share Posted May 14, 2016 Hey guys. I had an issue a while back where the alternator wasn't charging the battery. I traced the issue to a wire that came off the top of the positive driving battery terminal that became a harness. if you take a peek at the picture it may be a little clearer. the lug on top of the terminal that the green wire i am holding is touching is where this connected originally. two wires came off of this that went into the same harness. the wire missing is the one that was frayed so i took it off as originally i was going to try to repair the harness. my question is can i just bypass this? is it a fuse? i don't see anything in there other than wires connecting but then why does it exist if it's essentially not necessary? thanks so much. my rig is an 83 sunrader Quote Link to comment Share on other sites More sharing options...
zero Posted May 15, 2016 Share Posted May 15, 2016 I have no idea what I'm looking at in your photo. All Toyota trucks have at least one fusible link hard-wired in, between the battery-positive post and the alternator main post. 1983 has just one fusible link. 1988 has two, in series. No conventional fuse, and no circuit breaker. Just a fusible link. 50 amp rated for a 45 amp alternator, 60 amp rated for a 55 amp alternator, and 80 amp rated for a 60 amp alternator. 1983 model use shows the fusible link as "0.85R." I am not sure what that means except for the "R" for red. The "0.85" is likely the diameter of the conductor of the fusible link wire and that would make it AWG 12 gauge. Quote Link to comment Share on other sites More sharing options...
AbleThought Posted May 15, 2016 Author Share Posted May 15, 2016 3 hours ago, jdemaris said: I have no idea what I'm looking at in your photo. All Toyota trucks have at least one fusible link hard-wired in, between the battery-positive post and the alternator main post. 1983 has just one fusible link. 1988 has two, in series. No conventional fuse, and no circuit breaker. Just a fusible link. 50 amp rated for a 45 amp alternator, 60 amp rated for a 55 amp alternator, and 80 amp rated for a 60 amp alternator. 1983 model use shows the fusible link as "0.85R." I am not sure what that means except for the "R" for red. The "0.85" is likely the diameter of the conductor of the fusible link wire and that would make it AWG 12 gauge. ok i see. are you able to tell me if the harness i am holding in my hand is the fusable link? or if its just a connector of sorts i could bypass. Quote Link to comment Share on other sites More sharing options...
Maineah Posted May 15, 2016 Share Posted May 15, 2016 If it's a fuse link the wire is kind of squishy and the wire inside is quite small. Quote Link to comment Share on other sites More sharing options...
AbleThought Posted May 16, 2016 Author Share Posted May 16, 2016 2 hours ago, Maineah said: If it's a fuse link the wire is kind of squishy and the wire inside is quite small. this sounds about right! i probably need to get an aftermarket one at this point right? Quote Link to comment Share on other sites More sharing options...
AbleThought Posted May 16, 2016 Author Share Posted May 16, 2016 12 hours ago, jdemaris said: I have no idea what I'm looking at in your photo. All Toyota trucks have at least one fusible link hard-wired in, between the battery-positive post and the alternator main post. 1983 has just one fusible link. 1988 has two, in series. No conventional fuse, and no circuit breaker. Just a fusible link. 50 amp rated for a 45 amp alternator, 60 amp rated for a 55 amp alternator, and 80 amp rated for a 60 amp alternator. 1983 model use shows the fusible link as "0.85R." I am not sure what that means except for the "R" for red. The "0.85" is likely the diameter of the conductor of the fusible link wire and that would make it AWG 12 gauge. here is a bit of a clearer picture... photo A these are the two wires coming off of the female side of the harness. photo B here is an inside view of the female side of the harness that was in photo A.. *note this is still connected to the truck and is not the broken piece. photo C This is what broke.. the male end of the harness! *note i drew is an additional wire. it had two wires coming off the harness .. a green one (as you see) and a red one (the one i drew). they had the same type of connectors on the "harness side" and both wrapped into the same loop connector that is at the termanal side.. *side note i compared the thickness of the wire to some at the hardware store and it looks like 14 gauge.. photo D this is where the loop connector attached to the positive terminal on the driving battery. again both wires combines into the same loop connector. photo E this is just more of a birds eye view of the whole picture. question is .. is this a fusable link? if so would i have to replace these wires with aftermarket fusable links? *side note i checked my aternator and its a 45 amp. if this is not a fusable link can i just bypass this harness? ultimatly how can i fix this? thanks so much appreciate all the help Quote Link to comment Share on other sites More sharing options...
Maineah Posted May 16, 2016 Share Posted May 16, 2016 11 hours ago, AbleThought said: this sounds about right! i probably need to get an aftermarket one at this point right? Yes they actually sell fuse wire by amperage at auto parts stores. Fuse wire is kind of a thing of the past most every thing now uses body fuses for high current loads they did get pretty hot before they burn through so it was about safety. Quote Link to comment Share on other sites More sharing options...
zero Posted May 16, 2016 Share Posted May 16, 2016 I have no idea what that lead was added to your Toyota. It does not look OEM, and it does not show in the Toyota wiring diagram. Fusible links are more specifically engineered for circuits then fuses are. When replaced they have to be an exact gauge and length. What is a Fusible Link?A fusible link is a short piece of insulated low-voltage cable within an automotive wiring harness that is designed to protect the harness in applications where a fuse is unsuitable. In an extreme current overload situation, the conductor within the link is melted while the ensuing flame and spark is contained within the link's insulation. What size replacement fusible link should be used ?The automotive service industry recommends using the same gauge and length as the blown fusible link after the cause of failure is corrected. Are there any general guidelines for choosing a suitable fusible link?Typically, a given harness segment is protected by fusible link that is four gauge numbers smaller. A 14-gauge wire would be protected by an 18-gauge fusible link. A 6-gauge wire would be protected by a 10-gauge link, and so on. Odd number wire gauge sizes like 19, 15, 13 and 11 are counted when sizing a link. The length of a fusible link should not exceed 9".Can a fusible link be used to replace a fuse that blows frequently? In general, a fusible link should never be used to replace an automotive fuse unless authorized by a vehicle factory service bulletin. Safety and liability issues are involved. Can a blown fusible link be replaced with a MAXI™ fuse? While "MAXI" fuses have replaced most factory-installed fusible links in late model vehicles, they do not have the same performance characteristics as fusible links and should not be used to replace them unless specifically authorized by a vehicle factory service bulletin. Fusible links continue to be used in most starting circuit applications. Quote Link to comment Share on other sites More sharing options...
AbleThought Posted May 17, 2016 Author Share Posted May 17, 2016 7 hours ago, jdemaris said: I have no idea what that lead was added to your Toyota. It does not look OEM, and it does not show in the Toyota wiring diagram. Fusible links are more specifically engineered for circuits then fuses are. When replaced they have to be an exact gauge and length. What is a Fusible Link?A fusible link is a short piece of insulated low-voltage cable within an automotive wiring harness that is designed to protect the harness in applications where a fuse is unsuitable. In an extreme current overload situation, the conductor within the link is melted while the ensuing flame and spark is contained within the link's insulation. What size replacement fusible link should be used ?The automotive service industry recommends using the same gauge and length as the blown fusible link after the cause of failure is corrected. Are there any general guidelines for choosing a suitable fusible link?Typically, a given harness segment is protected by fusible link that is four gauge numbers smaller. A 14-gauge wire would be protected by an 18-gauge fusible link. A 6-gauge wire would be protected by a 10-gauge link, and so on. Odd number wire gauge sizes like 19, 15, 13 and 11 are counted when sizing a link. The length of a fusible link should not exceed 9".Can a fusible link be used to replace a fuse that blows frequently? In general, a fusible link should never be used to replace an automotive fuse unless authorized by a vehicle factory service bulletin. Safety and liability issues are involved. Can a blown fusible link be replaced with a MAXI™ fuse? While "MAXI" fuses have replaced most factory-installed fusible links in late model vehicles, they do not have the same performance characteristics as fusible links and should not be used to replace them unless specifically authorized by a vehicle factory service bulletin. Fusible links continue to be used in most starting circuit applications. i understand. so should i be "fusing" both sides? in other words i believe the wires at the female side are 8 guage (the white one) and the black is 10 gauge. so... should i be fusing both sides ( putting in a 12 gauge at male end of the harness before the white wire and 14 gauge before the black? or... should i only be fusing the negative side... so keeping the positive lead 8 gauge and putting in a 14 gauge before the black ( 10 gauge )? Quote Link to comment Share on other sites More sharing options...
AbleThought Posted May 17, 2016 Author Share Posted May 17, 2016 i managed to find a piece of the wire i was missing so now i know the gauge wire i need however i am unclear on one thing. is the fuse wire a different kind of wire? if so where would i get it? or is it the standard awg wire? pictures below thanks so much guys i think i'm close to a fix! Quote Link to comment Share on other sites More sharing options...
payaso del mar Posted May 17, 2016 Share Posted May 17, 2016 yes, the fuse wire is very much a special type of wire....different metallic composition, something that melts at low temp like Woods' metal. no, you can't use regular wire unless you want to risk your toyhome burning to the ground. the thing JD linked mentioned that fusible links ideally shouldn't be replaced by a large fuse....but if you can't find the correct fusible link wire, a big fuse is a hell of a lot better than nothing. Quote Link to comment Share on other sites More sharing options...
zero Posted May 17, 2016 Share Posted May 17, 2016 I've got a couple of rolls of 14 gauge fuse-wire on my shelf (old stock). As I understand it (and I could be wrong) - the metallic copper content is the same as any other wire. The difference is the insulation is melt and burn proof (or at least close). So when used correctly the wire inside melts and the insulation stays intact. Fuse-wire is usually four digits smaller, i.e. a circuit with 10 gauge wire gets protected with a certain length of 14 gauge fuse-wire. As Payaso del mar stated - a fuse can work. That "doom and gloom" in that stuff I posted is not my writing. Just a article about fusible wire that I reposted. One advantage to fuse-wire is engineers can adjust the length of get precision as to blow-time versus current that you cannot get so easy with a fuse. That being said - let's say you've got a 50 amp alternator. If you stick a 60 amp fuse in there - it will protect the circuit, and the worse that can happen is - it might blow prematurely and leave you with no charge. Length is critical. 14 gauge can carry 60 amps if at the correct length - or least close. Just make sure you replace with the same gauge as length as before. I posted earlier with the gauge specs from Toyota. Quote Link to comment Share on other sites More sharing options...
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