[LS Swap] Wiring Help!!!!!!!!
Thread Starter
Race Director
Joined: Dec 2005
Posts: 13,515
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From: Fisher, IL
[LS Swap] Wiring Help!!!!!!!!
Okay. Sorry if a lot of this seems basic but I'm new to wiring and i'm getting super confused. LS1 into a '69.
Trying to figure out what wires from the old harness need to still get hooked up along with the new LS1 wiring harness.
1. The picture from PSI harness only had 1 wire hooking up to the starter yet I have two...not sure if one is a motor ground? or if both hook to the large post on the starter solenoid.
(they are the two in my hand)
-From the old harness I'm showing the two large connectors and two small. I'm diving into my wiring diagram to figure them all out. Pretty sure my old solenoid had 4 posts and each one went to a different post. Not sure when now I only have 2 usable ones.
Trying to figure out what wires from the old harness need to still get hooked up along with the new LS1 wiring harness.
1. The picture from PSI harness only had 1 wire hooking up to the starter yet I have two...not sure if one is a motor ground? or if both hook to the large post on the starter solenoid.
(they are the two in my hand)
-From the old harness I'm showing the two large connectors and two small. I'm diving into my wiring diagram to figure them all out. Pretty sure my old solenoid had 4 posts and each one went to a different post. Not sure when now I only have 2 usable ones.
Thread Starter
Race Director
Joined: Dec 2005
Posts: 13,515
Likes: 11
From: Fisher, IL
And 2nd. Here's the fuel pump plug. Only 2 wires were labeled but even then I'm wondering If I can use the wires from my old fuel level gauge to steal power from?
where do the wires need to be connected to?
Where to white/green go?
Black ground to the frame? or...
And i'm pretty sure Red goes all the way into the wiring harness fuse area and that's where it gets it's power from?
where do the wires need to be connected to?
Where to white/green go?
Black ground to the frame? or...
And i'm pretty sure Red goes all the way into the wiring harness fuse area and that's where it gets it's power from?
Thread Starter
Race Director
Joined: Dec 2005
Posts: 13,515
Likes: 11
From: Fisher, IL
Okay here is what i've concluded so far.
New harness 2 connections=no clue...I assume hook up to large post on solenoid to power computer/harness.
Old Harness:
large red= hook up to solenoid..it goes to horn rely and eventually to ignition
large black=engine ground. might as well hook up to block.
small black= wire that went to the old coil. Leaving unhooked.
small purple= wire that goes to ignition/clutch synchro/neutral safety swith. I assume I need it but wondering if it goes on the only small post on the LS1 solenoid or not. I am assuming yes from the few threads i've seen searching.
New harness 2 connections=no clue...I assume hook up to large post on solenoid to power computer/harness.
Old Harness:
large red= hook up to solenoid..it goes to horn rely and eventually to ignition
large black=engine ground. might as well hook up to block.
small black= wire that went to the old coil. Leaving unhooked.
small purple= wire that goes to ignition/clutch synchro/neutral safety swith. I assume I need it but wondering if it goes on the only small post on the LS1 solenoid or not. I am assuming yes from the few threads i've seen searching.
Burning Brakes
Joined: Oct 2008
Posts: 1,037
Likes: 14
From: Mobile Alabama
And 2nd. Here's the fuel pump plug. Only 2 wires were labeled but even then I'm wondering If I can use the wires from my old fuel level gauge to steal power from?
where do the wires need to be connected to?
Where to white/green go?
Black ground to the frame? or...
And i'm pretty sure Red goes all the way into the wiring harness fuse area and that's where it gets it's power from?
where do the wires need to be connected to?
Where to white/green go?
Black ground to the frame? or...
And i'm pretty sure Red goes all the way into the wiring harness fuse area and that's where it gets it's power from?
Burning Brakes
Joined: Oct 2008
Posts: 1,037
Likes: 14
From: Mobile Alabama
OK
If you are using the module like this
It depends on if you are using the level sender on the new module or using your old fuel sender. If using the old sender, the way I did it, you only need 12v + from the fuel pump relay to the + wire and ground to the ground wire. The other two are just there because the original module used them.
If you are using the module like this
It depends on if you are using the level sender on the new module or using your old fuel sender. If using the old sender, the way I did it, you only need 12v + from the fuel pump relay to the + wire and ground to the ground wire. The other two are just there because the original module used them.
Thread Starter
Race Director
Joined: Dec 2005
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From: Fisher, IL
Not positive on the 69 starter wiring, but I think you had one small wire on both terminals feeding back into ignition. New starter only needs purple wire. The fuel pump - I am gessing that you have a pump module? Not just a pump. That would explain 4 wires. Power to pump from you fuel pump relay. Ground to ground. The 2 other wires would be fuel level in and out - hook to old fuel level wiring. Hope this helps, but hard to do over the computer.
It's an Fbody in tank fuel pump(exact pump pictured by you).
I eliminated my old fuel level so that sounds nice I may be able to hook those wires up to this and still use the gauge...
The wiring harness instructions say:
I assume the red wire goes in where the fuse panel says...Load/to fuel pump! That's easy enough.
Not sure what the insert wire for constant power(line) is for though.
Last edited by PUNISHER VETTE; Sep 3, 2012 at 02:26 PM.
Burning Brakes
Joined: Oct 2008
Posts: 1,037
Likes: 14
From: Mobile Alabama
Constant would be + feed line from fuse box
If you pull out the relay it has numbers next to the terminals.
87 is from the battery/fuse box
30 is to the pump
Thread Starter
Race Director
Joined: Dec 2005
Posts: 13,515
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From: Fisher, IL
Here is a picture pulled from PSI's website that they just updated with my harness. As you can see in the picture they have two lines labeled for the starter BUT one is obviously much much smaller(can't even see the terminal) so from what I am afraid of is they gave me two large terminal which is wrong... I assume one needs to be small=switched to ignition relay.
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Burning Brakes
Joined: Oct 2008
Posts: 1,037
Likes: 14
From: Mobile Alabama
One more thing, there should be a fuse (20amp?) in the line somewhere. Either in the feed from the battery to the relay or the load line to the pump. I am not sure how your harness is wired
Burning Brakes
Joined: Oct 2008
Posts: 1,037
Likes: 14
From: Mobile Alabama
Here is a picture pulled from PSI's website that they just updated with my harness. As you can see in the picture they have two lines labeled for the starter BUT one is obviously much much smaller(can't even see the terminal) so from what I am afraid of is they gave me two large terminal which is wrong... I assume one needs to be small=switched to ignition relay.
Thread Starter
Race Director
Joined: Dec 2005
Posts: 13,515
Likes: 11
From: Fisher, IL
There's an empty slot in my fuse panel I could easily add a fuse right?
Where do you suggest I tie in to get the 12v(line)
-I'm not actually sure I understand why that's needed still as there's plenty of other 12v wires they could have split and put one in there right?
Burning Brakes
Joined: Oct 2008
Posts: 1,037
Likes: 14
From: Mobile Alabama
I haven't seen anything about that...reasoning?
There's an empty slot in my fuse panel I could easily add a fuse right?
Where do you suggest I tie in to get the 12v(line)
-I'm not actually sure I understand why that's needed still as there's plenty of other 12v wires they could have split and put one in there right?
There's an empty slot in my fuse panel I could easily add a fuse right?
Where do you suggest I tie in to get the 12v(line)
-I'm not actually sure I understand why that's needed still as there's plenty of other 12v wires they could have split and put one in there right?
You are running a line down the length of the body to the pump. If the wire shorted (and there is no fuse to pop) it will heat up and burn. Your harness may have the fuse, but if the wire going into the relay, and the one going to the pump have no fuse, it is a problem. Yes, add fuse if there is not one
Burning Brakes
Joined: Oct 2008
Posts: 1,037
Likes: 14
From: Mobile Alabama
I will not sugest where or how to tie in your feed. It depends on where you locate you LS fuse box, and how much load (amps) you will pull. The load (amps) will be determined by how many things you have on the circuit. With only two relays (high amp switches) that means the rest of your circuits have have to come from somewhere. If you have three 20 amp cuircuits fed from the same line you would need 60amps capacity (wire size). Someone who used this harness or the maker would know better than me
Drifting
Joined: Dec 2007
Posts: 1,309
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From: Coastal Georgia
C2 of the Year Finalist - Modified 2020
Look on your fuse box for an open terminal labelled "BATT". That is constant power, and where I tapped into for my PSI harness. You can just extend the wire from your PSI harness to reach the fuse box (I think I used 12ga wire), and use a heavy duty spade connector to connect to the terminal.