As long as the truck is running, it will remain running if the link burns out because the alternator is supplying power. It might stall at idle as the alternator may not be able to supply enough power. On later vehicles, the alternator and chassis have individual fusible links. Early cruisers (before '73?) did not have a fusible link.
Look what I got away with - fusible link
- Thread starter subzali
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NAPA carries a range of fusible link wires in different sizes, and fusible link wire by the roll. It works for me.
I bought I believe a 14 gauge one intended for a GM from NAPA. It was a single 10" or so length. I then took apart the Toyota plugs and connectors and cut the GM wire in half (Toyota uses 2 shorter ones) and soldered/crimped it to the Toyota connectors, and put it back together. It's working fine.
I might have used 16. Pretty bad that I can't remember and it was only last week. I had a piece of the old one in my hand when I went in to Napa and they had 2 different gauges of GM links. I opened both up and bought the one that was the closest to what I had.
You '77 only has one fusible link. The late '78 models (sold as '79s) started using two links. AFAIK this continued with cat equipped models starting on 1/79.
Try calling Mark at MAD and asking his recommendation based on your system. Then buy his kit.
Try calling Mark at MAD and asking his recommendation based on your system. Then buy his kit.
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- #29
Who is Mark at MAD?
Today I went to NAPA, compared my primary wire with their wire rolls and found that it looks to be 12 ga. wire. So I got a 16 ga. fusible link, it's probably 6-8 inches long. It has a ring connector on one end, so presumably it is supposed to so directly on to the battery post? Then I'll solder it to the other piece of the primary wire that has the plug so that I can plug it into my harness.
Question though - my plug (pic at the top of this page) looks pretty shady. Is there any way I can disassemble the metal part of it from the plastic cover and re-crimp and solder it together? Or should I just cut both the fusible link plug and the harness plug off and use spade connectors, with shrink tubing or electrical tape around the whole shebang? I'm electrically inept so advice here would be welcome...
And my preference would be to keep it as stock as possible (with correct connectors etc.). If possible.
Today I went to NAPA, compared my primary wire with their wire rolls and found that it looks to be 12 ga. wire. So I got a 16 ga. fusible link, it's probably 6-8 inches long. It has a ring connector on one end, so presumably it is supposed to so directly on to the battery post? Then I'll solder it to the other piece of the primary wire that has the plug so that I can plug it into my harness.
Question though - my plug (pic at the top of this page) looks pretty shady. Is there any way I can disassemble the metal part of it from the plastic cover and re-crimp and solder it together? Or should I just cut both the fusible link plug and the harness plug off and use spade connectors, with shrink tubing or electrical tape around the whole shebang? I'm electrically inept so advice here would be welcome...
And my preference would be to keep it as stock as possible (with correct connectors etc.). If possible.
The initial white wire that is coming from your positive battery post would have come integrated into the factory battery cable and terminated after about ten inches in another connector set-up like what you have now. The fusible like had large connectors on either end. You still have one of those (white) and the black female connector attached to the white wire heading for your ammeter is original.
See if a factory positive cable is still available as it will have the correct connector already in place. Then you'll only have to find one connector for the other end of the link. After that you'll have to disassemble the brass spades from inside the connector housings to make your new link. This requires a little flat bladed tool that you can make if you know what it looks like or sometimes you can do it with a paper clip. You can get them from auto parts stores. They are called wiring terminal extractors or something like that.
Crimp new brass spades onto the fusible link wire and snap them into the connector housings and plug them in. Get a good quality crimping tool if you're trying to make a factory crimp. Mine was made by Packard Electric. Sourcing the large brass male and female spade connectors used to be easy thru Wrangler Power but they were bought out by a company in Oregon who decimated the product line and I don't know where to get them any more. Maybe someone here does.
Well, seems like a simple idea but I would have never thought . . . Thanks for the info. Seems to be a good idea to carry at least 1 spare on the rig too. I see them online at only about 3 bucks. Well worth it. thanks again - I'll be getting this fixed asap. I know the wiring on my old pig is just a torch waiting to happen. how big of a task is it to change the harness? I guess Ken can comment best. Sorry Ken.
- Thread starter
- #35
So I found out what happens:
I had the truck running and pulled the fusible link off the battery. It must have spiked the voltage because one of my side marker bulbs burned out
Anyway the truck kept running with all accessories. But when I turned it off everything went off - lights etc. And it wouldn't start again. Nada. Nothing. No power at all. While it was off I touched the link to the battery and toggled the lights on and off.
Hope that helps or adds data to the story for those who were wondering...
I had the truck running and pulled the fusible link off the battery. It must have spiked the voltage because one of my side marker bulbs burned out
Anyway the truck kept running with all accessories. But when I turned it off everything went off - lights etc. And it wouldn't start again. Nada. Nothing. No power at all. While it was off I touched the link to the battery and toggled the lights on and off.Hope that helps or adds data to the story for those who were wondering...
subzali, off course it kept running, the alternator was supplying power at that point. It will not start, because there is no power from the battery to the ignition switch.
In other words, the large battery cable from the positive side of the battery goes down to the starter. It only provides power to the starter motor, that is it. The small fusible link wire is a two way street for power from the battery, or power from the alternator. When the engine is off, or the alternator is not functioning due to broken belt, internal failure, or voltage regulator issues, the battery will run the truck until it is dead. When starting, the battery is needed to trun the starter motor, provide power through the fusible link wire to the fuse block for the iginiton curcuit, which sends power to the coil and distributor and to the starter selonoid on the starter. The starter selonoid, activiates when you go to start, it makes two copper contacts on a shaft jump over and make energy flow into the starter motor from the large battery cable. The large battery cable does not provide any other power to the vehicle.
Once running, then the entire positive battery cable could in theory be pulled off, as the engine should continue to run on the alternator, or at least the fusible link wire. But I would not recommnd this, as it will affect grounding and such, and you could cause some funny problems with you charging curcuit.
Vehicles that just die if the fusilbe link burns up, have problems someplace that caused that kind of short, that extend beyond just a lack of juice from the battery. Something has shorted, the alternator is haywire, or the battery is dead.
In other words, the large battery cable from the positive side of the battery goes down to the starter. It only provides power to the starter motor, that is it. The small fusible link wire is a two way street for power from the battery, or power from the alternator. When the engine is off, or the alternator is not functioning due to broken belt, internal failure, or voltage regulator issues, the battery will run the truck until it is dead. When starting, the battery is needed to trun the starter motor, provide power through the fusible link wire to the fuse block for the iginiton curcuit, which sends power to the coil and distributor and to the starter selonoid on the starter. The starter selonoid, activiates when you go to start, it makes two copper contacts on a shaft jump over and make energy flow into the starter motor from the large battery cable. The large battery cable does not provide any other power to the vehicle.
Once running, then the entire positive battery cable could in theory be pulled off, as the engine should continue to run on the alternator, or at least the fusible link wire. But I would not recommnd this, as it will affect grounding and such, and you could cause some funny problems with you charging curcuit.
Vehicles that just die if the fusilbe link burns up, have problems someplace that caused that kind of short, that extend beyond just a lack of juice from the battery. Something has shorted, the alternator is haywire, or the battery is dead.
Anybody know where I can find these large spade connectors to rebuild my fusible link? I am trying to rebuild my fusible link (and make a spare) and locating a source for the right size connectors that are compatible with the factory plug is ... driving me crazy.
Thanks! -Josh
Anybody know where I can find these large spade connectors to rebuild my fusible link? I am trying to rebuild my fusible link (and make a spare) and locating a source for the right size connectors that are compatible with the factory plug is ... driving me crazy.
-Josh
Found a source in another thread if anyone is interested. Thanks LostMarbles! Not sure how to linkback to it yet, but the thread name is: Ammeter/fusible-links ......late model 40-series.
-Josh
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