I have an 89 Volvo 790 and for about a month now, there is a constant dinging noise that occurs whenever the key is in the ignition. There are no lights on on the the dash and the only way to make the dinging stop is to take the key out of the ignition. So whenever I am driving, I hear this constant ding, ding (sounds like when you open a door while driving). Anyways, I know that the dinging is coming from behind/underneath the stereo (where the fuses and wires are kept). Any help on diagnoising this dinging or at least turning it off)?? Please help, thanks!