Originally Posted by SSsuperchargedEi
i had the same problem with mine. but it turned out that the + terminal on the battery was leaking acid and eventually fell off. sounds dumb, but it'* true
This same thing happened to my 1999 SSEi shortly after I bought it. Check to make sure the battery connections are tight, and not leaking. You might also try loosening the terminals to make sure the bolt into the battery isn't corroded in place. Acid will do this if it'* leaking and you don't catch it soon enough.
It was a major pain for me -I had to cut the battery cable and put a new terminal on.
I wonder if all 1998 & 1999 Bonneville SSEi (any 1998 and 1999 owners for that matter) should check this out and if it'* a problem with more than say, 10, a report should be made to GM. This is, only if the original battery is still in the car.
BTW, the exact same thing happened to my friends 1999 Regal LS. The original battery had the positive terminal leaking acid and I replaced the battery for him back in January, and the car only had around 70k on it.