I have a 2012 Express Van, 6.0L Gas, 6L90 Trans.
Recently noticed that my reverse lights are staying on when trans is in park and shutoff. Struggling to find quality wiring diagrams or tech data. Suspect neutral safety switch inside trans attached to trans valve body but would like to verify before starting to replace parts. Has anyone had this problem? Any advice would be appreciated.
Thank you, MT

 

did you check gmupfitter.com?

 

Thank you. I had not. I took a quick look and it appears to be a great resource.