I recently purchased an 02 diamante and the battery light was coming on randomly. Each time I would shut off the engine and restart it and the alternator would begin charging again. I found that the battery cables would not tighten on the top posts so I bought some top post shims from AutoZone. When I went to install them, I found that someone had tin foil wrapped around the positive post thinking this would work. I removed the foil, installed the shims and haven't had any problems. I hope this information will help someone with the same issue.