A wire harness assembly system (50, 250) comprising: at least one grid tile (60, 260) for receiving at least one repositionable accessory to route wires, wherein the at least one grid tile (60, 260) has a top (62, 262), a bottom (64, 264), and sides (66, 266); wherein the at least one grid tile (60, 260) has a plurality of keyed holes (70, 270), the plurality of keyed holes (70, 270) extending from the top (62, 262), through the at least one grid tile (60, 260), to the bottom (64, 264) of the grid tile (60, 260) for receiving the at least one repositionable accessory to route wires along the at least one grid tile (60, 260); wherein the at least one grid tile (60, 260) has a locking surface on the bottom (64, 264) of the at least one grid tile (60, 260), wherein the locking surface has a plurality of ramps (82, 282) and a plurality of grooves (80, 280) and complements the plurality of keyed holes (70, 270) for maintaining the at least one repositionable accessory in a locked position; and a locking mount (110, 310) installed in the at least one grid tile (60, 260) for receiving the at least one repositionable accessory to route wires, wherein the locking mount (110, 310) has a keyed lower portion for mating engagement with the keyed holes (70, 270) and locking surface of the at least one grid tile (60, 260), whereby the installed locking mount (110, 310) is configured to be rotated to a locked position; wherein the keyed lower portion of the locking mount (110, 310) has a shaft that includes side projections with an angled top portion; and wherein the side projections and angled top portion of the locking mount (110, 310) are configured to slide over one of the plurality of ramps (82, 282) and into one of the plurality of grooves (80, 280) in the locking surface to secure the locking mount (110, 310) to the grid tile (60, 260). at least one grid tile (60, 260) for receiving at least one repositionable accessory to route wires, wherein the at least one grid tile (60, 260) has a top (62, 262), a bottom (64, 264), and sides (66, 266); wherein the at least one grid tile (60, 260) has a plurality of keyed holes (70, 270), the plurality of keyed holes (70, 270) extending from the top (62, 262), through the at least one grid tile (60, 260), to the bottom (64, 264) of the grid tile (60, 260) for receiving the at least one repositionable accessory to route wires along the at least one grid tile (60, 260); wherein the at least one grid tile (60, 260) has a locking surface on the bottom (64, 264) of the at least one grid tile (60, 260), wherein the locking surface has a plurality of ramps (82, 282) and a plurality of grooves (80, 280) and complements the plurality of keyed holes (70, 270) for maintaining the at least one repositionable accessory in a locked position; and a locking mount (110, 310) installed in the at least one grid tile (60, 260) for receiving the at least one repositionable accessory to route wires, wherein the locking mount (110, 310) has a keyed lower portion for mating engagement with the keyed holes (70, 270) and locking surface of the at least one grid tile (60, 260), whereby the installed locking mount (110, 310) is configured to be rotated to a locked position; wherein the keyed lower portion of the locking mount (110, 310) has a shaft that includes side projections with an angled top portion; and wherein the side projections and angled top portion of the locking mount (110, 310) are configured to slide over one of the plurality of ramps (82, 282) and into one of the plurality of grooves (80, 280) in the locking surface to secure the locking mount (110, 310) to the grid tile (60, 260).