1989 chevrolet s 10 truck memory lead

Hello All.

I have a 1989 Chevy S10 that I purchased 3 months ago. It came with an aftermarket CD player, 200 watt amp and a 10" subwoofer/enclosure. The Kenwood cd player that was installed played fine as long as the ignition stays powered but I noticed when you shut the vehicle off for about 15 mins. or so, All of my personal settings are lost (bass,treble,subwoofer volume, etc).

I have since removed that cd player and installed my old Sony Xplod from my Chrysler. The wiring harness in my truck fits right into the back of the Sony Xplod stereo and plays beautifully but it also loses it's settings when the ignition is switched off. I checked the S10 Stereo information page and it says that "orange" is the Constant 12V....If I'm not mistaken though, My S10 has a red wire that was straight-wired to the brake socket in the fuse panel. Of course, Brakes are always hot but red is not mentioned in the list of wires.

I wanted to know if they guy I bought the truck from had it wired incorrectly and if so, How do I get the settings to remain in memory after shutting the ignition switch off?