Why does my chime go off randomly? "Bing Bing Bing"

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Recently purchased 1996 T&C LXi from original owner. Garage kept well maintained only 77,000 miles. Car had not been driven for 6 months before I bought it. Installed new battery when purchased. When driving the chime goes off randomly for different lengths of time and will happen several times in a few minutes or maybe not again for several minutes. No other indicators, no lights flashing, instrument panel works fine. I have tried turning things on and off while the chime is on but can't get a relationship to the problem. Occasionally the chime will stop when I turn something on but I think it is coincidence. Instrument cluster was replaced about 4 years ago. I have replaced the C pillar light switches, the battery terminals even tried a different battery, no improvement. Does no power to the BCM for 6 months cause it to go bad? I am down to the BCM or seat belt module as the possible cause. I have only driven the van about 100 miles in 5 weeks. The longest drive was about 18 miles total. Thanks for any you can give.