Hello, I've recently replaced the twelve-volt battery in my '1994 318 is' but unfortunately there have been some electrical issues ever since. Primarily, the stock BMW radio no longer makes a sound nor plays a cassette?!? What's more perplexing is that it apparently has power because the LCD screen lights up. I imagine the problem may be due to detaching the old battery incorrectly and perhaps causing a short circuit? If anyone has experience with this type of situation, I'd greatly appreciate any advice.