Depinned engine harness --- now ... ??

[FAKKY]

Eric
Your thread post in that older thread #8 - pics below



Now my truck .... using a DIY fuse block from BP automatoive. The Purple starter wire just feeds into the fuse block from the wiring harness and exits with the rest - not actually fused or linked into block here. Keeping clean. Straight passthrough.



This is the NSS for 4l65e



=========

So Im still a little confused about how to connect the NSS and ignition correctly.

Im guessing the 12GA purple wire I have now in top pic goes to the relay #30.

But then Im confused how you've marked purple wire to starter in that thread pic from ignition going to range sensor .... Im guessing thats due to a different range sensor than I have ?

Blue/Green connector 2007 lq4/4l65e

#12 wire on my connector is pink wire. Like this * I think*

[FAKKY]

If I understand the diagram correctly it would mean (20% shot geeting right here)

12v wire KEY ON wires gets spliced into pink wire at pin #11 to active power signal.

12v Ignitition wire from ignition goes to pink wire at pin #12 to activate ignition for starter.

If transmission is in PNP .... then Pin #1 DARK/GREEN will activate relay on pole #86 and then activate the starter wire on pole #30.

Therefore
My existing purple wire from starter would just go to pole #30 on a starter relay.
I would splice and extend the dark green wire #1 on NSS to pole 86 on relay.

Then the two power wires to pin #11 and pin #12 on the NSS from my ignition switch.

[ls1nova71]

I'm not 100% following you, but that diagram I drew that you posted is for the older NSS, the kind with 2 plugs, so that's why the numbers are different. With the one you have, you would hook the wire that comes from the ignition switch (the one that has power when you turn the key to "crank") to the pink wire #12. Then #1 the dark green wire would go to the relay pin 86. Those are the two wires that control the relay, so you would then make 85 go to ground and run a constant 'hot' to 87. The last terminal, 30 would go to the starter solenoid on the starter itself. I hope that clears it up.

[FAKKY]

Think it does. I think I got the wiring wrong though ..... should be wire

#9 LT_GRN PNP switch signal
not
#1 DK_GRN - PNP/Clutch switch start signal

is that right ?


Why do you have to splice into the wires - meaning - I would have thought that the source engine vehicle (hummer in this case) would run the same way so there would already be wires to hook into.

If Im still not getting it - drop me a PM and I'll reach out - tried last night but your PM box was full )

thanks eric

[ls1nova71]

You dont need #9, you only need #1 and #12. You need to splice the wires because it's a swap, not a regular vehicle. If you leave the whole stock fuse box in tact then yes, the wires are in there, but if you're doing a stand alone, you dont use that. You just have to put power on the 12 wire, the 11 is for the shift interlock which I assume you dont have?

I cleared out some of the messages in my inbox. The messages about speedo kits seem to pile up in there.

[FAKKY]

Originally Posted by ls1nova71

You dont need #9, you only need #1 and #12. You need to splice the wires because it's a swap, not a regular vehicle. If you leave the whole stock fuse box in tact then yes, the wires are in there, but if you're doing a stand alone, you dont use that. You just have to put power on the 12 wire, the 11 is for the shift interlock which I assume you dont have?

I cleared out some of the messages in my inbox. The messages about speedo kits seem to pile up in there.

Not sure what a shift interlock is ......
I kept thinking where does that no 11 and 12 wire end/terminates ...... seems like you would just find that and then send 12v wire to that. Wasnt sure if I just spliced into it at the transmission end if it would complete the circuit type deal.

I get the principal of your drawing ..... but stuff like that literally searching forums for half the day.

[ls1nova71]

The shift interlock is a solenoid on the column that makes you have to press the brake pedal to shift out of park. Both 11 and 12 terminate at the under hood fuse box, but like I said, since it's a swap, I am assuming you dont have that. Also, being a swap, it needs to be wired a little different than factory. In an original application starting would be controlled by the BCM. The way I described hooking it up just uses the NSS as a switch for the starter relay. I just looked at that drawing I made that you posted and it is in fact for the later switch, only #12 is pink at the switch rather than purple, but other than that it will work if you wire it that way.

[FAKKY]

Thanks Nova.

I dont know why but the overall concept and relay to send a signal from the PNP switch to the relay to activate the solendoid makes sense.

Just splicing those wires for 12V at the switch side ...... really made me think I was misunderstanding something. In my head it was

1) "Surely it gets 12v from the main ignition source ... so once I wire the 4-5 hot and key on wires..... It will get 12v like the rest of the harness ... so no splicing ? .. but then on the diagram looks like its a seperate wire spliced in"

2) "If I do have to splice at the PNP switch side and apply 12v ign/key on .... why ? .... where does the wire go to complete that circuit - and how would that have worked in the original vechicle ......"

etc

So spent 4 hours trying to understand wiring schematics and all I could find was PNP switch on C1 wire 34 ..... but no idea what that was for and how to read and how it tied to 11 or 12 (because I dont think it did) etc

[ls1nova71]

Originally Posted by FAKKY

Thanks Nova.

I dont know why but the overall concept and relay to send a signal from the PNP switch to the relay to activate the solendoid makes sense.

Just splicing those wires for 12V at the switch side ...... really made me think I was misunderstanding something. In my head it was

1) "Surely it gets 12v from the main ignition source ... so once I wire the 4-5 hot and key on wires..... It will get 12v like the rest of the harness ... so no splicing ? .. but then on the diagram looks like its a seperate wire spliced in"
In the original vehicle with the original under hood fuse box it would, but since most swaps use a stand alone harness, or a modified factory harness, they don't have provisions for the NSS or back up lights.

2) "If I do have to splice at the PNP switch side and apply 12v ign/key on .... why ? .... where does the wire go to complete that circuit - and how would that have worked in the original vechicle ......"
You only need a 12v ign/key on, on pin 11 for the back up lights. The 12v ign/key on on pin 12 will be the starter wire from the ignition switch and will only be hot when the key is turned to the 'crank' position. Originally it was an ign/key on, but you cant wire it that way without the BCM. Originally the BCM would complete the ground when cranking the starter was necessary, but to simplify it in a swap, you just ground the other side of the relay,

etc

So spent 4 hours trying to understand wiring schematics and all I could find was PNP switch on C1 wire 34 ..... but no idea what that was for and how to read and how it tied to 11 or 12 (because I dont think it did) etc

C1 34 on a truck harness is just a signal wire to the PCM, you don't need to do anything to it. There are a few of them that go directly from the NSS/range sensor to the PCM. I think you must have seen on LT1Swap where it says that wire can be programmed for a single wire park/neutral signal. That is for if you don't have the switch on the side of the transmission, you run one wire to an external NSS that is grounded on the other side, so it provides a ground signal to the PCM when the transmission is in either park or neutral. It serves the same purpose as the wires that you don't need to touch on your NSS. It doesn't function as a neutral safety switch in that it in no way controls when the vehicle will start or not start. This is the way LS1 Camaros and TAs are wired.

[FAKKY]

"'but to simplify it in a swap, you just ground the other side of the relay,""

^^ I *think* that was the part I missing.

I have family in Chillicothe/Tina MO - about 70 mins from you ...... if I get back up there with a day to spare in August ..... I will pay my beers

Im in FL.

[ls1nova71]

Ok, so you think you have it figured out now? If you get up this way, hit me up. Been to Chillicothe many times, they have a nice show in the middle of summer, but there's been a lot of flooding in that area lately.

[FAKKY]

Originally Posted by ls1nova71

Ok, so you think you have it figured out now? If you get up this way, hit me up. Been to Chillicothe many times, they have a nice show in the middle of summer, but there's been a lot of flooding in that area lately.

Lord.
For both our sakes and our poor heads I hope so.

Should be up there around August as we head through to wyoming.
Yeah I've seen some pretty crazy photos that I wouldnt have believed ..... I heard stories when my wife was a kid on last big floods about jetskis in the corn fields ..... supposedly this was worse. Seeing bridges and roads you have travelled completely underwater is surreal.