LS won't crank

[D-n-Tyke]

These threads may help you if it is the neutral saftey switch on the 4L80 trans. They are from when I was researching how to wire up my NSS.

http://67-72chevytrucks.com/vboard/s...d.php?t=845747

https://ls1tech.com/forums/conversio...l#&gid=1&pid=4

[57FleetsideC4]

Originally Posted by D-n-Tyke

These threads may help you if it is the neutral saftey switch on the 4L80 trans. They are from when I was researching how to wire up my NSS.

http://67-72chevytrucks.com/vboard/s...d.php?t=845747

https://ls1tech.com/forums/conversio...l#&gid=1&pid=4

Thank You. I looked at the one with the starter relay and it looks like the dark green wire becomes hot when in park or neutral so I think that part is good. What feeds that yellow/black wire is where my problem must be. Steve

[D-n-Tyke]

Originally Posted by 57FleetsideC4

Thank You. I looked at the one with the starter relay and it looks like the dark green wire becomes hot when in park or neutral so I think that part is good. What feeds that yellow/black wire is where my problem must be. Steve

Are you using the factory fuse box out of the donor vehicle? Or are you using a standalone fuse/relay block as part of the modified LS harness? Similar to this (https://lt1swap.com/fuseblock_obd2port.html)

[57FleetsideC4]

Originally Posted by D-n-Tyke

Are you using the factory fuse box out of the donor vehicle? Or are you using a standalone fuse/relay block as part of the modified LS harness? Similar to this (https://lt1swap.com/fuseblock_obd2port.html)

This is modified factory harness and I found the problem. There is several wires that have to be connected to the truck to run. The purple start signal wire from the switch was corroded and broke inside the harness (I was poking around and the purple wire pulled out of the harness. Just had to solder the wires together and piece of shrink tube and all set. Thank You for the replys. Steve

[D-n-Tyke]

Originally Posted by 57FleetsideC4

This is modified factory harness and I found the problem. There is several wires that have to be connected to the truck to run. The purple start signal wire from the switch was corroded and broke inside the harness (I was poking around and the purple wire pulled out of the harness. Just had to solder the wires together and piece of shrink tube and all set. Thank You for the replys. Steve

Nice. Glad you got it working. Wiring gremlins can be a pain.