Wire Gauge Chart for Car Audio Systems - dummies When wiring your car audio system, using the proper gauge wire for an amplifier is critical. To avoid problems and get the best sound, determine the fuse ratings of your amplifiers and their distance from the battery and refer to the following chart to determine the proper power-wire gauge. For Gauge wire used for stock radio? | Tacoma World Oct 27, 2011One is the reverse signal wire (from a connector under the drivers seat) and the other is the VSS wire (from behind the glove box). I would like to run the same gauge wire and was just wondering what gauge is typically used by Toyota on their harness for the radio? The Metra wire harness I have #17-1761 looks like maybe 18 gauge, but not sure.