When I was putting back my aftermarket stereo I noticed several wires that must have connected to the factory stereo/cassette player. There is a brown wire and tan wire that are stuck together, I'm guessing these wires were for background lighting on the factory stereo but I shouldn't have to use these, right? There were also yellow, black, and gray wires. Now correct me if I'm wrong but here's what I think each one is for: yellow is for power when ignition is on, gray is for constant power (i.e. clock time and radio station presets), and black is for ground. Let me know if this is correct. Thanks.