Ls swap wiring help

[Carolina68]

I’m doing an Ls turbo setup. And I’ve pretty much sorted through all the wiring. On this diagram I’ve circled two wires in. One is black with a bulb fuse near the junction block and it says engine harness connection. Do I need this wire if I’m not using any of the stock engine harness?

The other wire is black with a white stripe and it showed fused in the diagram but mine is not fused. It just ties into the fat red wire that runs to the junction block. Not sure what the black/white stripe wire is for?

I’ve searched and searched but no definitive answer. Thanks for any help and maybe if your not sure you can steer me in a direction to find the info.

[LockDoc]

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I am going to move this to the LSx Swaps forum. The only thing that circuit is for is the stock Amp gauge.

LockDoc

[Carolina68]

Thanks lockdoc. Sorry I don’t post here a lot. Next time if it’s Ls related I’ll put it there.

[LockDoc]

Originally Posted by Carolina68

Thanks lockdoc. Sorry I don’t post here a lot. Next time if it’s Ls related I’ll put it there.

No problem. If you scroll down a ways in this forum there is a thread titled "Fuel line recommendations". Check post #17. Member "Wasted Income" is building a Turbo truck also. There is a link at the bottom of his post to go to his build. If you have any questions on the Turbo install I'm sure he could help you out.

LockDoc

[chev-obsession]

Originally Posted by Carolina68

I’m doing an Ls turbo setup. And I’ve pretty much sorted through all the wiring. On this diagram I’ve circled two wires in. One is black with a bulb fuse near the junction block and it says engine harness connection. Do I need this wire if I’m not using any of the stock engine harness?

The other wire is black with a white stripe and it showed fused in the diagram but mine is not fused. It just ties into the fat red wire that runs to the junction block. Not sure what the black/white stripe wire is for?

I’ve searched and searched but no definitive answer. Thanks for any help and maybe if your not sure you can steer me in a direction to find the info.

I just did this!

The black and black with white stripe wires are for the ammeter in the gauge cluster, it’s supposed to show if there is current draw or battery charging.... something like that.

If your not a purist, I’d take an actual voltmeter from a square body (don’t quote the exact year but like ‘76 and up have them) and replace the ammeter and just run ignition power to it. Then remove the black wires going into fuse block on the firewall and disconnect from the battery. To answer your question, no you don’t need them for your truck to run. Not sure what you did for wiring, but pretty much everything on the external voltage regulator can be removed.

What alternator do you have? How many pins does it have?

[Carolina68]

Originally Posted by chev-obsession

I just did this!

The black and black with white stripe wires are for the ammeter in the gauge cluster, it’s supposed to show if there is current draw or battery charging.... something like that.

If your not a purist, I’d take an actual voltmeter from a square body (don’t quote the exact year but like ‘76 and up have them) and replace the ammeter and just run ignition power to it. Then remove the black wires going into fuse block on the firewall and disconnect from the battery. To answer your question, no you don’t need them for your truck to run. Not sure what you did for wiring, but pretty much everything on the external voltage regulator can be removed.

What alternator do you have? How many pins does it have?

Thank you chev-obsession. That is great news. I have a scram speed LS alternator that has been turned into a one wire with a Holley 1 wire harness with the resistor. I do not need any volt reg right now as I’m going Holley terminator and pulling the old cluster to do a 7” Holley screen the old volt reg is already ripped out. I basically just went through the old school engine harness and clipped them all at the firewall. Kept all the stuff I needed like lights, horn, etc. so my plan is to clip the black wire and black with white stripe wire since they are not needed. And my battery is relocated to the bed so I have to run that fat red wire back to the battery. Do it need a fusible link? I prefer a fuse if possible but what size?

[chev-obsession]

I cant speak on the fusible link, other than I would be running a fusible link over a fuse. Do your research on that part.

I'd have to see how the alternator is setup but you might need the brown (alternator exciter) wire coming from the firewall. If you aren't going to use the brown wire, id terminate the brown wire entirely at the ignition switch... that is where it gets the power from.

As for the ammeter wires, I would make sure they aren't connected to the battery in any fashion and take the terminal out of the black plastic firewall connector (that goes for any wires that you don't want to be using). I would not leave an open end on a cut wire. Terminate the wires where they get their power and verify with a multimeter that they have/don't have power before and after you do your cutting.

[Carolina68]

Originally Posted by chev-obsession

I cant speak on the fusible link, other than I would be running a fusible link over a fuse. Do your research on that part.

I'd have to see how the alternator is setup but you might need the brown (alternator exciter) wire coming from the firewall. If you aren't going to use the brown wire, id terminate the brown wire entirely at the ignition switch... that is where it gets the power from.

As for the ammeter wires, I would make sure they aren't connected to the battery in any fashion and take the terminal out of the black plastic firewall connector (that goes for any wires that you don't want to be using). I would not leave an open end on a cut wire. Terminate the wires where they get their power and verify with a multimeter that they have/don't have power before and after you do your cutting.

Thank you!! I’ll get them all sorted out and Ill probably use that brown exciter wire and also I’ll figure out the fusible link as well. You’ve helped a lot. I appreciate it.