1995 Pontiac Bonneville no dash or tail lights

Two years ago dash and tail lights started working sometimes and sometimes not. Removed headlight switch. Found connector to be melted to the switch. Replaced switch and connector. One year later lights started acting up again. Pulled switch out of dash and found no problem, figured connector may have come loose because lights started working again. About one year later, two weeks ago, lights started acting up again, pull the switch and noticed the connector had started to melt again. Switch looks ok and wiring to the switch showes no sign of over heating, insulation on wires is not melted. What kind of gremlin do I have?