Sometimes when I start my car the electronic thing that has the outline of your car and the odometers on it lights up totally and won't go back to normal. If I start to drive the warning bell comes on and won't stop because it thinks that something is wrong.

Today when it did it, I tightened up the battery cables and it still didn't work. After running for about 20 minutes, it suddenly went back to normal.

It has done this a few times now. The battery cables are now tight, but the black one appears to be quite rusty (corroded??).

Any ideas of what might be up. It runs fine but if the warning bell goes off and won't stop, you have to turn the radio up loud so it does not drive you nuts!!!!