Cable

My intention is to install an auxiliary battery for camping in a 20 17 Silverado 2500 using GM's parts. GM's discussion of Removal/Installation procedure of Positive Auxiliary Battery cable, PN 23386298, on a gas truck with RPO K4B does not mention any connections that would energize the Auxiliary Battery Run Relay, item 10 in the attached drawing. The procedure only mentions connecting the cable to positive battery terminal on the under hood fuse block. The Auxiliary Battery Run relay is needed to energize the Auxiliary Battery relay, item 7 in the drawing. In versions prior to 2014 this energizing voltage came from a connection made to B4 on the Under Hood Fuse Block. Can anyone shed some light how this relay gets it's energizing voltage and where and how the connection is made?