Impala/Caprice Installation Page 10
Next remove the front and rear door carpet retainers, raise the center pillar carpet retainer and remove the back seat. This photo shows the front retainer off.
This photo shows the rear seat and rear door carpet retainer removed.
Loosen the center pillar upper trim piece bottom only (it pulls straight out, but not off), this allows the lower panel to be raised a couple of inches.
Next pull the front carpet back, lay the gray wire next to the large wiring harness. The factory harness goes into a plastic channel if you can open this channel run the gray wire through there, otherwise run the gray wire between the plastic channel and the seat, the wire is safe outside of the channel.
Note: be careful when feeding the gray wire through openings to avoid stressing the end connector wires.