The Fusible Link Thread [merged]
05-08-2007, 09:30 PM
#42
Le Mans Master
The '78's thru '82's have a real problem with the white 8 pin Molex connector sitting just above the heater/evaporator box having corroded/burned connection. IIRC, the main power feed to the fusebox coming up from the fuse-link on the starter runs thru this connector. Check the heavy red wire for a burned connector. Should be hot (alive) all the time. Check both sides of the connector.
05-08-2007, 09:46 PM
#43
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St. Jude Donor '07
Hmm...is there some sort of way they're rated as to what it takes to burn it up?
I want to run a nice heavy wire from my CS144 to the starter, and I'm trying to figure out how to keep that safety functionality.
I want to run a nice heavy wire from my CS144 to the starter, and I'm trying to figure out how to keep that safety functionality.
05-08-2007, 10:21 PM
#44
Melting Slicks
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On my car the central power distribution point is a lug on the horn relay, and I increased the wire gauge feeding from the alt to that lug.
05-08-2007, 10:29 PM
#45
Le Mans Master
A fusible link is just a thinner wire. I forgot the calculation. but lets say you starter wire is 16 gauge...the fusible link is a 14 or 12 guage (depending on calculation)wire soldiered in. The theory is that if you over load the system you will have a controlled burn in the harness on the thinner wire.
Jim
Jim
A fuseable link is a wire composed of a solder-like material which melts without a chance of burning. A wire consisting of copper , when subject to an overload, may burn and start a fire. Not good.
05-09-2007, 12:27 AM
#46
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St. Jude Donor '07
Batman I don't think you need a heavier gauge link there just because you're installing a higher amp alternator because that point is not the central point of power distribution. I know later model cars are wired differently than mine so I can't be specific, maybe someone with similar wiring can give you a good answer.
On my car the central power distribution point is a lug on the horn relay, and I increased the wire gauge feeding from the alt to that lug.
On my car the central power distribution point is a lug on the horn relay, and I increased the wire gauge feeding from the alt to that lug.
05-09-2007, 01:01 AM
#47
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14ga between alternator and battery. IIRC, you don't want the wire here to be any bigger because the alternator will put out too much current for the battery to "absorb." In your case, don't you want bigger wiring in the amplifier circuits??
Last edited by Z-man; 05-09-2007 at 01:05 AM.
05-09-2007, 07:40 AM
#49
Drifting
Just for yuks I checked my service manual. Not only does it say NOT to use just any old wire, it also says that the fusible link also has some sort of special insulation that will not burn.
05-09-2007, 08:18 AM
#50
Melting Slicks
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My car is the same way, but I plan to hook two amplifiers up from the battery positive terminal...I'd like to make sure that the path from the alternator, through the starter terminal to the battery is as robust as possible. Bubba has attacked the wiring at the starter, anyway...so it needs some repair work. I might not even have a fuseable link there anymore...
I wouldn't remove any links from your existing harness.
05-09-2007, 08:30 AM
#51
Team Owner
Batty, do NOT run your amps off the battery post, run them off the horn relay spot, leave your stock (hopefully) starter wiring alone....
and increase your wire to the horn relay for the extra currents being drawn....another valid way is take the amps directly off the alternator output stud....
IF you get a alternator whine in the speakers, you may well have to upgrade the amps, OR the input devices...filter the power supplies, etc....aftermarket cheep sound systems often have that affliction, and it's hard to get rid of....but decent designs do not....it's about how they do the power supplies in the electronics....something you/I can not change....not cheep anyway....
and increase your wire to the horn relay for the extra currents being drawn....another valid way is take the amps directly off the alternator output stud....
IF you get a alternator whine in the speakers, you may well have to upgrade the amps, OR the input devices...filter the power supplies, etc....aftermarket cheep sound systems often have that affliction, and it's hard to get rid of....but decent designs do not....it's about how they do the power supplies in the electronics....something you/I can not change....not cheep anyway....
05-09-2007, 08:40 AM
#52
Le Mans Master
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Hey Batman;
Just an opinion here, but this is what I would do.
An optima is a good idea, but I would not swap it if your battery is good.
Make sure your lead from the alternator to the battery is in good shape and large enough to carry the current for the amps and battery charge current, that will be 20amps + the amps, probably a 14 or maybe a 12 ga wire. Put a fuse link from the term block to the battery and tie the amps to the term block, they should be fuse protected.
Run another 12 ga from the alt to the battery cable on the starter and protect it with a fuse link or a CB.
What that willl do is split the load from the alternator between the 2 circuits and shorten the current path for everything else in the car. I asume you already have done the relay conversion for the lights, fans etc, if not you should do that too.
I'll dig up the drawing I am going to use for mine, more or less the same thing as above. Its still under construction, but I'll post it tonight,
Just an opinion here, but this is what I would do.
An optima is a good idea, but I would not swap it if your battery is good.
Make sure your lead from the alternator to the battery is in good shape and large enough to carry the current for the amps and battery charge current, that will be 20amps + the amps, probably a 14 or maybe a 12 ga wire. Put a fuse link from the term block to the battery and tie the amps to the term block, they should be fuse protected.
Run another 12 ga from the alt to the battery cable on the starter and protect it with a fuse link or a CB.
What that willl do is split the load from the alternator between the 2 circuits and shorten the current path for everything else in the car. I asume you already have done the relay conversion for the lights, fans etc, if not you should do that too.
I'll dig up the drawing I am going to use for mine, more or less the same thing as above. Its still under construction, but I'll post it tonight,
05-09-2007, 10:24 AM
#53
Team Owner
The rule of thumb is four points difference. You will probably find that the red wire to the starter is 10-gauge and the (smaller) fusible link will be 14 gauge. It is NOT just a smaller copper wire.
05-09-2007, 10:48 AM
#54
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I think I found it. I used my test light and probed the fuseable links. I found the link that goes into the fuse box and started probing about 6 inches from the firewall. when I got about 2 inches from the forewall, no light......I pinched the wire and it feels like there is no wire in there. This must be the feeder for the fuse box????? It either case I'll replace this and go from there. Do you think I'm going in the right direction here? Thanks, Larry
05-09-2007, 11:35 AM
#56
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VIOLA!!!! The fuse link that goes into the firewall side of the fuse box was burnt. There is about 1 inch of good wire coming out of the box....should I replace the whole back of the box which has the wires going to the alternator and headlights? I don't think I feel real good about a patch job....please let me know what you think...Thanks, Larry
05-09-2007, 12:35 PM
#57
something besides age probably caused it to fail; i think i'd try to find that as well. if your on a budget and the remaining wire is okay, you should be okay with the fix. using relays for headlights would help reduce the load on that wire, etc.
05-09-2007, 02:00 PM
#60
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The difference is that fusible links are NEVER supposed to fail. Said another way, there should be no reason for a failure in the line with a fusible link unless someone working on the car has made an error [generally, has caused a direct short]. Fused circuits have devices on them that can fail and cause an overload. Fix the device and replace the fuse. There are lots and lots of GM cars still on the road that have never had a fusible link failure and never will... unless Bubba gets to them!