Re: hooking up cd player, where to hook up yellow wire???
The standard designation for these days is the red wire hooks up to a "switched hot" meaning it only has power when the ignition is on. This red wire is power for the actual cd player and intenal amp itself. The yellow wire is intended to be a "constant hot" meaning it is hooked up to a + 12vdc source that is always on regardless of ignition switch position. The yellow wire powers the clock and maintains internal voltage in the unit to keep the presets in memory. The unit will operate with only the red wire and ground (black) hooked up, but everytime you turn off the unit it will lose the clock setting and presets. You can even hook up both red and yellow to a constant hot but this would allow you to leave the CD player turned on anytime and drain the battery (not a problem if you remember to turn off the player when not in use...but just another thing to forget and cause trouble). The yellow wire, itself hooked up to a constant source, pulls very little current (milliamps) and will take a very long time to drain a significant amount from the battery (days, if not weeks). If you operate your boat frequently I would not worry about the yellow wire draining the battery. If you are laying up the boat for a significant amount of time you probably disconnect your battery anyhow, in which case you will have to reset the clock and presets when you hook everything back up to go boating again.