The first step to replace the rear electrical center or junction block requires disconnecting the battery negative cable. The procedure for gmc envoy xl requires left second row seat removal but chevrolet trailblazer and gmc envoy users need to set their left second row seat to cargo position. The process begins with opening the rear electrical cover after which technicians remove the battery terminal nut from the junction block allowing them to extract the
Body Control Module (BCM) from the same area. Before proceeding remove the junction block from the block base by first unlatching its tabs then loosening its retaining bolts from the electrical connectors. Remove the Instrument Panel Harness Connector, mobile telephone harness connector, Body Wiring Harness Connector and console harness connector and headliner harness connector from the junction block. Remove all retaining nuts that fasten the floor studs to the block base then remove the base from the floor panel. To install the procedure requires setting the block base onto floor studs before tightening retaining nuts to 10 n.m (88 lb in). Safely connect the mobile telephone harness connector to the junction block base together with Instrument Panel Harness Connector and console harness connector and Body Wiring Harness Connector and headliner harness connector . Secure the junction block onto the block base then bead it down with three bolts which require tightening to 3.5 n.m (31 lb in). Thebcm installation at the rear electrical center includes connecting the junction block battery feed terminal nut while tightening it to 10 n.m and restoring the center cover. When working on chevrolet trailblazer or gmc envoy vehicles position the left second row seat into a passenger state while gmc envoy xl owners should replant their left second row seat. Reconnect the battery negative cable as the final step.