Wiring Question

[1971Stepside]

I have been doing searches on the page, but not really finding what I am looking for. I know I need to re-wire my LS harness for the motor, but what harness do I need for the truck itself? If I buy a stand alone for the motor/transmission what harness is best for the truck and the LS tie in? I looked at the American Auto Wire harness for our trucks, but it seems like I don't need a bunch of those wires. Confused on the best way to go for the LS and truck together and not spend an arm and leg.

[66 C10 383]

The LS harness is usually stand alone. It doesn't tie in with the rest of the truck. You can either replace just the truck wiring that needs to be replaced or completely rewire the whole truck.

American Auto Wire sells what they call the Factory Fit which is the original style wires. Some of them are pricey. If you need to replace very many circuits, the Classic update may end up being cheaper in the long run.

M&H Electrical Fabricators also sells individual stock wiring. http://www.wiringharness.com/

[1971Stepside]

I need all the wires for the truck front to back. Wasn’t sure how things like the starter and alternator used both harnesses. I would assume they both do?

[sprint_9]

I used an AAW Classic update, I have really liked it so far. You do end up not needing most of the engine side of the chassis harness, but the wires are easily removed and only add up to like 6 or so wires that you remove. I like using a specific harness for the truck that way you get everything laid out in the prints, all the connectors are new and made for the application, the update series uses blade fuses, has 6 various power circuits that really come in handy for accessories like power locks, aftermarket gauges, power windows, etc.

Your truck wiring will need 12v from the battery, and the starter solenoid wire to start the truck. Thats really it from the chassis side of things. The engine will also tie into the positive starter terminal or battery, the engine runs the alternator cycling but your 12v power ties into the starter or the battery. The engine will also need to tie into keyed ignition power, brake light switch, NSS switch, and a couple others I cant think off the top of my head.

Attached are a couple pictures, these are all specific to how I wired my own truck so there are Im sure several variables.

Frist pic is the engine side of the chassis harness, 12v to my starter, and purple ignition wire to the starter solenoid. Tan is the brake pressure switch.

Second pic is my starter, I ran most of my power off of the starter stud. From back(closest to engine) to the front. Black wire hard to see is the engine harness 12v tie in, 2 gauge cable from the battery, purple is starter solenoid from chassis, orange is 12v power from alternator, brown on the very bottom hard to see is the 12v tie in for the chassis.

[1971Stepside]

Very helpful Sprint. I appreciate it. So, in theory I could get my engine running before I ever put the cab and chassis wiring together.

[Jstock85]

Sprint im glad you posted that man. Im working on fuel system now and then wiring so hopefully ill be doing that within the next few weekends.

I want to ask you a couple questions to verify im not going to screw this up. The purple wire in your pics goes from the fuse block bulk head to the small bolt on the starter and the big read wire goes straight to the battery?

[sprint_9]

Originally Posted by 1971Stepside

Very helpful Sprint. I appreciate it. So, in theory I could get my engine running before I ever put the cab and chassis wiring together.

Yea it could be mocked up.

Originally Posted by Jstock85

Sprint im glad you posted that man. Im working on fuel system now and then wiring so hopefully ill be doing that within the next few weekends.

I want to ask you a couple questions to verify im not going to screw this up. The purple wire in your pics goes from the fuse block bulk head to the small bolt on the starter and the big read wire goes straight to the battery?

Yes, the purple wire comes from the bulk head. Which on the inside of the truck comes from the ignition switch.

The big red wire on the bulk head goes to the 12v battery side of my starter. It's the brown wire in the post above, it switches to brown as on the starter end is a fusible link. I choose to run most of my 12v battery power from the starter stud to clean up the battery connections.

[TCCGRIZ]

Ok I'm going to keep an eye on this thread .

[Jstock85]

Originally Posted by sprint_9

Yea it could be mocked up.



Yes, the purple wire comes from the bulk head. Which on the inside of the truck comes from the ignition switch.

The big red wire on the bulk head goes to the 12v battery side of my starter. It's the brown wire in the post above, it switches to brown as on the starter end is a fusible link. I choose to run most of my 12v battery power from the starter stud to clean up the battery connections.

Sprint Sorry for my elementary questions! Im just about to start my wiring and I want to be 100%...

Purple wire is from ignition to bulk head to starter small bolt. Did you use a fusible link here also?

The red wire from the fuse block goes to the large bolt on the starter with a fusible link and this powers your PCM ?

The large 1 gauge wire coming off the large bolt on the starter goes directly to the battery?

[sprint_9]

Originally Posted by Jstock85

Purple wire is from ignition to bulk head to starter small bolt. Did you use a fusible link here also?

No fuse link. This wire only has power when you start the truck.

Originally Posted by Jstock85

The red wire from the fuse block goes to the large bolt on the starter with a fusible link and this powers your PCM ?

This wire powers the chassis harness, PCM power is through the engine harness.

Originally Posted by Jstock85

The large 1 gauge wire coming off the large bolt on the starter goes directly to the battery?

Yes

[Jstock85]

Ok thanks! Thats about how is exactly how I plan to wire mine.

Did you put any inline fuses on your engine harness?

[sprint_9]

Originally Posted by Jstock85

Did you put any inline fuses on your engine harness?

I believe it also has a fuseable link on the starter.

[Jstock85]

Ok thanks.