jatPPV2012
Member
Welcome from Iowa.
until you can get your hands on the FSM, Here is a link to the wiring diagrams from www.gmupfitter.com for your year of vehicle.
https://www.gmupfitter.com/files/media/photo/484/2012_LD_ElectricalPickupsChassisCabs_100813.pdf
https://www.gmupfitter.com/files/media/photo/460/2012 Police Specifications Manual 9-29-11.pdf
Great! Thank you. Appreciate the link info.

Thank you to you guys for the advice and the pics. They really helped. Got the wiring from under the radio, found the cut light brown wires, spliced them back together and HONK! It works!