Best way to wire up a charge wire

[GM Guy]

Hey guys,

The project 98 K2500HD had a bad alternator, and a really crappy charge wire setup, which I want to correct.

So I wanted to ask you guys, what guage should I use, and how important is it to use a fusible link? is there any pre-made offerings? I see PT wiring solutions does not offer a seperate charge wire on his site, maybe Bruce offers it if I ask nicely.

Also, I am kinda "electrically challenged" so now for the dumb question: what could occur in the pickup's electrical system that would cause the alternator to burn out?

The previous alt. was a bigger framed alt (the CS144?) that was not factory, and it was cobbled in, the stub harness was adapted (IIRC one loose wire) and the charge wire may not have been making the best connection.

Basically i am a little gun-shy about sticking the new one in till I know why the old one failed.

Finally, for testing purposes, and sort of a poor mans fusable link, can a guy use a 12 guage wire to make sure the system works?

Any input appreciated, thanks!

 

[Steve83]

This photo album contains a mod you don't need to do right now, but it also contains a lot of the info you're looking for:



Use AT LEAST the same gauge (but not substantially larger) wire as the factory did for your alternator's output. The fusible link wire can protect the truck if the alternator goes above max output (which isn't likely), but its main purpose is to protect the battery & keep the truck running if the alternator fails as a dead short (burned diodes or wreck). It's as important as any other circuit protection, and not prohibitively expensive, so there's no reason to omit it. I still have several feet of orange, so if you can't find it at a reasonable price locally, e-mail me.



That caption describes how to size a fusible link, and how it's different from common wire. If you don't have the proper link, use a megafuse or CB temporarily.

.

You'll have to define what you mean by "burn out" before I could guess why it happened. What were you doing when it failed? Did it actually overheat? Did you open it up & look inside? There's very little info about the truck in your post or signature - what modifications (particularly electrical, but try to list EVERYTHING) does it have?

 

[FellowTraveler]

I used the GM UPFITTERS C/K manual published 12/98 and made my own brackets. I removed the fuse links and use a dual marine MEGA FUSE block to fuse each gen/alt.

Main gen/alt has both tach & charge control exciter to PCM the second gen/alt has only the charge control exciter tapped into the main gen/alt each unit runs at half the amp output they would have if they were run as singles.

 

[FellowTraveler]

IMAGE of GMT400 C/K dual gen/alt wiring.

 

[GM Guy]

thanks for all the info guys, very much appreciated!

IDK how the alt. failed, as this is an auction bargain pickup and it was dead (no charge or alt function) when I bought it. The aluminum is all black around the plug, almost like smoke or fire poured out the back.

 

[jrsavoie]

I use 2 OEM style cables with the fusible links from GM's at the junk yard. 2 eyelets will easily fit in the rubber cap at the alternator. I run one to each battery.

I usually use the original and then just add a 2nd wire. If the originally is kaput then it gets them both.