I'm working on finishing my LS stand alone wiring harness for a turbo Colorado build. The setup is a 2006 Colorado, Gen III 5.3l from a 2003 Silverado w/ 4l80e from 2005 Chevy express van. Ive come to the neutral safety switch part of the harness and Id like to keep the switch if possible. The connectors on the stand alone harness are the old dual plug style. The switch on the 4l80e is the newer single plug style. The original trans on the Colorado has a newer style single plug I've snipped off and saved. From searching it seems that GM combined the two plugs into one in the new single style. My question is can I use the new style switch with my older style harness or do I need to buy the older style switch and keep the two plug setup?

 

If you want to cut the ends off your harness, then you can splice the newer plug on it. They do the same thing, just different plugs. You would have to get schematics for both and compare them so that you get them wired up right, but if I remember correctly the colors match up pretty close.