Why does the Battery Light and the brake light go on at the same time on a 2003 Kia Sedona?

Weird electrical problems too

Ha! I just had this happen yesterday! Well, today my car died in traffic and wouldn't restart or even turn over. It's in the shop as I type, and they are telling me it's the alternator. I'm not sure I believe them. Why would that cause weird lights to come on? Other conditions: hot weather, A/C on. We also replaced the original mfr's battery about a month ago, and I now wonder if that was related to the alternator or whatever problem is causing current issues.

Well....... They are most likely correct on the alternator. I just placed my 4th alternator on my 02 Sedona.When they go and the battery is getting low. weird things happen with the electrical system. Also when the battery light comes on, it also has the brake light come on as well. I just finally went on line and purchased a go OEM alternator by USA Alternator and it finally fixed the problem.