New CD Instalation

I was switching my current CD player to a mp3 player, in a car I just got (Doubt it matters... but incase it does, Mazda MX-3, 93) It had a wire harness in it, So it was a pretty basic, simple install. Although I did crosscheck the wires in my new Mp3 players instalation instructions, against the Diagram I found online for my car. I ran across one problem - The constant 12V, doesn't work. I got my Mp3 player going by crossing over the ACC power into the yellow wire... but as you know, that doesnt save any of my information (IE: last song I was on/Radio presets) It looks like my old CD player...was installed this way also. I'm pretty sure it saved the current place in a song though... however I had the car for 2 days before I upgraded...so I'm not sure. I have a Volt meter, And the yellow wire (12V constant) Has no power in it at all. The red Wire (ACC) Has the correct voltage. I checked the fusebox... and the fuse did not look blown. I took the fuse out of my windshield wipers, (Same voltage) Put it in...and it didn't work still. Am I going to have to install a new wire into the fusebox? I'm not very knowledgable about cars... however I do have electronic experience. I'm tempted to cut open the 12V constant wire... see if it has power without the harness on...and eventually I think I'll have to do that. Would the easiest way be to install a new wire and lead it to the CD player? If it is...anyone have any webpages with instructions? I only know how to use a volt meter very basically... not sure if I know how to use it to find a constant 12V... Any help appreciated, Thanks :)

Check and see if you have a second fuse box under the hood and see if there is a wire labeled memory or back up. If not run a wire directly to the battery with a fuse in line as close to the battery as possible.There is no such thing as free installation!

I'm about to undo the whole CD system, And check each wire to see if it's got 12V or not. I got my uncle to install it since I've never installed one before... but looks like he didn't know exatly what he was doing ;) don't think he even unhooked the Car battery... Could he have fried something there? I'll look under the hood for a second fusebox first, though. The CD player that was in it... the yellow wire has a fuse attached to it. I'm not very good at electronics... so would that fuse make a difference? I don't think so if the wire doesnt read any power at all... I'll look into if theirs another fuse box under the hood... then I'll re-check all the wires for a 12V... If that dont work... I guess I'll have to try to run the wire from the battery. As for that... Seems a little complicated. What do I do... just attach a wire to the batter (With a fuse along the wire) And run it through the dashboard or something? Any instructions/guides online or anything?... I almost feel like just going to an installer... but in Canada it costs $100... and paying $100 just to get a simple wire put in, seems like a waste. I've fixed electronic stuff before... know a lot about wiring/proper wiring.... I'm usually doing it with computers/Electronics. Pretty confident I can do it without frying something, just unsure of which fuse/wiretype to get...and how I'd get it from the battery :\ wouldn't it be easier to go from the fusebox?

Just went under the hood, and found a Wire connected to the battery... The wire led to a fuse, and it was blown. I'm presuming this was my constant 12V.... I went and changed the fuse, Now the yellow wire shows as "1.5" volts on the voltmeter.... is something else messed up? running out of ideas on what to check....