A wire harness protector having an open slide trough closed by a removable cover, and containing an internal wire harness carrier attached to the harness, for example by taping, and connected to the cover to slide in the trough when the cover is closed. The carrier is generally L-shaped, and the trough has a wire slot formed in a sidewall thereof generally parallel to the guide slot in the cover, such that the wire harness is redirected laterally within the trough by the carrier, with an incoming end sliding longitudinally in the trough, and an outgoing end sliding laterally through the wire slot in the side wall. The wire harness protector according to the invention is especially useful for protecting and controlling wire harness slack found between hinged and sliding surfaces in a vehicle, for example doors, hoods and trunk lids.