Exposed Alternator/Starter Wires

[Eddie86]

Hi, just picked up a 1986 K10 Silverado in need of some love. I'm a gearhead from way back but have not had a squarebody. Am in the process of repairing some of the factory (appears to be) wiring harness - specifically the alternator/starter solenoid wiring. I've removed the starter and upon inspection of the wires attached to it, saw two wires that had black bullet-type covers in the middle of the wire that had "14" on one and "16" on the other. I'm assuming that's the gauge. The issue is that directly behind the bullet is about an inch or two of exposed wire that actually looks like it was that way from the factory. (Hopefully it's clear in the picture) I thought maybe the wire pulled out from the bullet sheath but it did not. Not sure why there would be exposed wire. 

Also, I plan to use Cross-Link GXL wiring for the repairs. Sound right? I need to replace the ring connectors for these wires at the starter connections due to corrosion/frayed and am planning too use non-insulated, double crimped ring connectors with heat shrink. Does anyone have a good source for the connectors? I'm assuming I'd need heavy duty or high heat. Thanks!

[75gmck25]

Those are fusible links.  A #14 link protects a 10 gauge wire and a #16 link protects a 12 gauge wire.  They appear to be the stock GM factory installation.  However, they should not have any bare wire showing.

Those wires should be connected to the starter and go up through a metal tube (about the size of your thumb) that is bolted to the back of the engine.  The tube goes up to behind the valve cover and then the wires come out and go across to the alternator (charge wire) and over to the fuse box.  The metal tube is designed to protect them from exhaust heat, but they still take a beating.

Bruce

[Eddie86]

Bruce, thank you for the quick reply. I plan to replace the links back at least to where the exposed wire starts. What would you recommend for a replacement link? I'm getting my wire from Del-city.

[bd]

Welcome to the forum, Eddie. 

Adding to Bruce's comments, the "black covers" are molded urethane insulators that enshroud the butt splices joining the fusible links to the primary harness.  Fusible link is manufactured from high strand count copper alloy wire that is jacketed by very-high-temperature Hypalon insulation.  Do NOT substitute any other type of wire or gauge.  With very rare exception in limited applications, fuse links are 6" long regardless of gauge.  Terminate the wires using tin electroplated, soft copper or brass terminals available virtually everywhere.  You can purchase bare terminals or insulated terminals and simply strip the insulation off before crimping.  Make firm mechanical crimps that won't pull apart and then solder sparingly using 60/40 rosin core solder.  Shrink seal using (marine grade) dual wall, adhesive lined, polyolefin heat shrink tubing that overlaps the wire insulation at least 3/8".  If you need to replace any of the primary harness wires, GXL and SXL are excellent choices.

For materials sources, see What's everybody's favorite source for buying wiring/looms/etc.?

[Eddie86]

Thanks bd. Did some searching and found a prior how-to thread. So to confirm, use a 16 gauge and 14 gauge fusible link wire to replace the current insulators after removing them?

My only other question is how link wire gauge size selection would be affected on that #16 GM link that has two wires attached to it. I'm assuming that the two wires coming into it are both 12 gauge? Does that not matter with link size selection the fact that it's protecting two wires vs one? I guess not if that's the way the factory did it? Thanks

[bd]

The fusible links are the 6" lengths at the ends of the wires connecting directly to the solenoid 3/8" battery cable stud.  The black bulges are just butt splices, hence sever the harness wires on the primary wire side of the splices. 

Two of the factory harness wires share one link.  The gauge of the shared link is four sizes smaller (numerically larger) than the wires it protects.  So, the 12-gauge wire pair is protected by a single 16-gauge link.  Alternatively, you could protect each 12-gauge wire separately with individual 16-gauge links.

Is How to make a Fusible Link on this forum the reference you discovered?

Local automotive parts stores should have preassembled 6" fuse links for purchase in the proper gauges so that you don't have to buy 25'+ spools.

[Eddie86]

Bd, my apologies. I did notice that and should have mentioned that. I will inspect all of the remaining portions of that harness for any additional breaks. I plan to connect my link to where that break (arrow) is so my link may actually be between 6 and 9”. I’ve read on other reputable sites that the link should be no longer than 9” (I’ve seen 6 and 9 as a maximum) so I’m thinking I should be okay. I’ve ordered Pico links that are 72” in length to have extra. I’ll get appropriate connectors and attach per your instructions. Thanks.

[Eddie86]

And yes, that was the link on this forum to which I was referring.

[bd]

Just bear in mind that increasing the length of a given fusible link by a factor of 1.5 (9"/6"=1.5), increases its resistance by a factor of 1.5, decreases its current capacity by 33% (C=V/1.5R).  This occurs because fusible link exhibits a given resistance per unit length that is considerably greater than the wiring it protects, as it must in order to function effectively as a fuse.  Increasing the length of any wire increases the net resistance of the local run in direct proportion.  Six inches is the industry standard length for fusible links in all but a very few specialized applications.  Because of the repercussion, it isn't generally wise to alter that relationship.

The wire in the image you posted has been damaged from excessive heat exposure, probably due to proximity with the exhaust exacerbated by chemical exposure and/or insulation abrasion.  You would be best served by replacing the entire length of wire running between the starter solenoid and the firewall junction block or bulkhead connector, as the case may be.  I recommend SXL copper wire for that specific application because of its increased insulation thickness.  You may also benefit from a starter heat shield and/or thermo-sleeve loom.  In addition, you should verify that there is no active exhaust leak from a compromised manifold or warped flange.

[Eddie86]

Agreed. Makes more sense in the long run to replace. I will be replacing all the wires with GXL and adding additional sheathing and then will be able to use 6" fusible links. Thanks again.

[Eddie86]

Thanks for all the help. I have everything prepped but am having a difficult time finding a comparable replacement for the terminal ends at the solenoid connection points. Both the 14 and 16g fuseable links were connected to the larger double crimp, non-insulated ring terminal in the picture. That was sitting on the main 3/8 lug. The other was a regular 12g wire connected to the other smaller double crimp, non-insulated ring terminal in the picture. That was on the "S" #8 lug. These terminals (which I'm assuming are OE) are beefy and cannot be bent by hand. I would like to use the same exact type terminals, adding marine grade heat shrink wrap. I cannot find these things anywhere. These terminals just seem like they would be the best connection for this application (heavy duty and prob high heat rated). They lasted 32 years! I can find somewhat similar ones for the smaller one but all of the 3/8 rings are either too thin around the edge or don't come in double crimp. I've seen this type of connection called "European style"? Not sure. Anyway, any links (I've tried Del-city, autowire, summit, etc... with no luck) or advice would be much appreciated. Thanks. 

[Henry]

Hi Eddie86:
It may be difficult to find exact replacement terminals. If you cant find them, I would suggest looking at replacements from West Marine. They have a full line of terminals and since they are for marine application they are all good quality. If you dont have a store near you I am sure they have a decent website to browse.
Regards,
Henry

[Eddie86]

Henry, thanks for the information.

Ed

[bd]

http://www.terminalsandconnectors.com/Products/Search?searchBox=ring+terminal

https://www.mouser.com/Search/Refine?Keyword=delphi+ring+terminal

http://terminalsupplyco.com/Store/Default.aspx?CAT=UNI030050&PCAT=78717#Categories

[VileZambonie]

Napa should have what you need. I think harbor freight carries the self sealing heat shrink tubing now too.