wire connection to alternator

I have been having problems with my alternator for a while. After developing a bearing noise, i replaced it with a brand new one from autozone. when I was replacing it I noticed that the wires feeding into the plug were labeled (+) and (-) (on the plastic part of the plug, not the wires them selves.) The wire feeding into the positive side was skinny and had a black sleeve. where as the negative side was fat and had a red sleeve. I assumed that the wires must have gotten switched at some point so I pulled them out of the connector and put the fat wire on the (+) and the skinny one on the (-). I was hoping someone could double check this for me and let me know before I get in and drive to work tomorrow. I looked for a diagram, but was unable to find what I needed. I know this discription is rather unclear so congratulations are in order for whoever can decipher it.

Thanks.

Mike B.