Ever since I bought my FJ60 2yrs ago the brake warning light in the dash cluster is always dimly lit at idle but not when driving. Wondering if this is the alternator or battery? The battery has no date marked on it from what I can tell and I was going to replace until I found out that it's a pretty good battery (Napa legend premium 84) and problably has life left I'm guessing. Anyway, If alternator, what is the best replacement? I wouldn't mind having a little more amperage if possible but want plug n play. Thanks.