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Old 05-11-2015, 02:42 PM   #1
Tilt
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Join Date: Jul 2014
Location: Dayton, TX
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Starter/Alt wiring?

I'm trying to get some stuff done on the truck today since its raining. I have a couple questions.

For the starter, I have the wire from the battery cable connected to the big lug and the purple wire from the original '86 harness that comes from the bulk head connected to the small lug. Is there any need for the red wires from the original '86 harness that connected to the big lug? The original '86 wire came off the big starter lug with two fuse-able links, one ran to the junction block on the firewall, the other ran to the plug for the '86 alternator and spliced off and went to the bulk head.

On the alternator, I need to run a new wire from the little red box on the + battery cable to the lug on back of the alternator. The original '86 harness had the wire that went to this lug, but it came from the junction block on the firewall with a fuse-able link that had another red wire spliced into it that runs to the bulkhead. Do I need to splice the wire going to the bulkhead into the new wire coming from the red box on the battery cable to the lug on the alternator?

For the 12v keyed, Would the heavy pink wire that comes from the bulkhead and went to the original spark control box be what I need to tie this into? I keep reading to use the wire that went to the coil for this. Would this be that wire?

I've read thread after thread and looked at the wiring schematics til my head feels like it's going to explode. Any and all help would be GREATLY appreciated.
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'85 GMC short bed.
'86 Chevy Step Side Custom Deluxe
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Old 05-11-2015, 05:53 PM   #2
mongocanfly
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Re: Starter/Alt wiring?

That big red wire that connects from the big starter lug to the junction box on firewall is what carries power to the trucks original electrical system so yes you need that. From there it goes to your fuse panel.For the alternator wire I simply ran a heavy wire from my alternator lug to this same firewall junction. No need to tie it into the red box on your battery cable. It will feed back to the battery from there. And yes the big pink wire that goes to the old distributor is used as your switch on power.you can check that with a volt meter if you are unsure. It will show 12v when switch is on and 0v when switch is off if you have power to that firewall junction box. That is what i used power all my switch on power needs. I ran it back into the cab and hooked it to a junction strip and then connected everything to it under the dash...makes my head hurt trying to remember this stuff...
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