Saab also had a battery warning light, like most cars. However, if the battery was not charging, the light would not come on. Also if the bulb burned out, your alternator wouldn't work.

My saabs, of the 5 I own, only have working lights in about 2 of them. One has no tacho (from factory), one no speedo (broken)

Turns out you pretty much dont need any of that stuff anyway.