Impala/Caprice Installation Page 5
This is what it should look like on the outside of the grommet, wrap some electrical tape around the grommet and wiring to help prevent water from infiltrating into your trunk.
Wrap the new wiring harness a couple times around the factory harness. The
shorter wires are for the left turn signal and the longer wires for the right
turn signal. Route the right turn signal wire along with the factory wiring
harness between the bumper and body.
Shown is the new wiring harness wrapped around the factory harness as viewed from under the car (drivers side). Besure to wrap the new wiring harness around the factory harness to support it and prevent it from dangling under the car (do not over wrap - over wrapping shortens the overall lenght of the new harness, and the wire may end up being too short to complete the job properly).
This part could test your patience. This view is the factory harness and the new harness passing through a small channel over the fuel filler tube. It's difficult to explain and photograph, but I believe you'll see it when you're under your car running the wiring. I've found you can facilitate running this wire from behind the license plate by pulling on the plastic bumper - you can remove 2 phillips screws there also.