My opinion is that red wire is a Hot lead either off the battery or the fuse box. A few tj models, including mine, a 2000, have 2 hot leads off of the fuse box behind the glove for accessories. There is a red, which is always on, and a blue, which works off key in pos 2. Trace that red wire to see if its live, was most likely hot for a cb, fog light switch or something. The little computer port is for the mechanic scanner for the codes if i'm not mistaken.