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I will preface this with:
Donor: 2004 6.0/4L80E out of a 2500 Suburban
Recipient: 1969 Checy Suburban (396/TH400)
I spent the day following LT1Swaps instructions and videos and modifying the stock LS harness. When I was all done cleaning it up I had 2 mystery wires left towads the end of the harness by the fuse block, a dark green wire and a gray wire. I believe they were from either the C150 or C151 connector I cut off. I rang the mystery wires out and found that they went to the neutral saftey switch connector. I am not sure what they do and what I should do with them? In the picture the one marked GR is where the gray wire rang out, and G is where the green rang out.
Can someone give me some guidance on this? Appreciate it.
Also, if I wanted to run the 4L80's NSS inplace of the original NSS on the column of the 69 suburban how hard would that be to do and how would I do it?
Are you using the Vehicles original starting (crank) circuit? When I did my "71 Camaro swap I just used the neutral safety switch from the car at the console shifter. I did use the trans PNP switch and harness also. The yellow high lighted circuit is the dark green wire from the PNP switch on trans to the starter relay
Are you using the Vehicles original starting (crank) circuit? When I did my "71 Camaro swap I just used the neutral safety switch from the car at the console shifter. I did use the trans PNP switch and harness also. The yellow high lighted circuit is the dark green wire from the PNP switch on trans to the starter relay
Starting out I was probably going to juat use the original safety switch on the 69 Suburban. However, if it is simple to hook up the 4L80e saftey switch I think I would like to go that route in the long run.
Main thing from this post was I wanted to make sure I didn't leave any wires disconnected when i completed my swap that would make it so the truck wouldn't run or drive.
You need to run a starter relay to use the newer NSS. It works better than a column mounted one because its more accurate, but a little more work to hook up.
You need to run a starter relay to use the newer NSS. It works better than a column mounted one because its more accurate, but a little more work to hook up.
I had found this diagram you had drawn up a while ago. is it still an acurate diagram? Am I reading it right that I would need to add a wire to the #12 pin of the NSS connextor that comes from the ignition key crank pin?
From the tons of research I did trying to figure this out (and TONS of thanks to lsnova71 for all his knowledge shared in multiple threads) this is what I have determined and wired my truck accordingly:
Gray wire (NSS pin 10) is the power supply wire to the back up lights.
Dark green wire (NSS pin 1) is the trigger signal wire going to the starter relay I added into my harness.
Light Green (NSS pin 9) (I originally thought went to back up lights) goes to the shifter interlock on newer cars
Thanks for updating this. I bought a swap harness 13 ish years ago. I still have never fixed my NSS or backup lights, and although I have a shift interlock, I have it zip ties currently.
While my truck is apart for this year's improvements, hopefully I can correct all of that as well. Thank you
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Help with Neutral Saftey Switch Wiring 
