Could be a couple of different things depending on your deck. 1: Headlight triggered switch that causes the keys on your deck to light up (most probable) 2: Headlight controlled dimmer switch that causes the lights on your deck to dim when your lights are turned on. usually the remote trigger will be labelled "accessory or ACC" and the memory wire us usally labelled "12V+, unswitched, or memory"o No: HTH