2007 Lucerne CXL. and 1995 Lesabre currently, past 1973 Riviera, 1968 Riviera
Check the main harness connection from the assembly to the wiring harness. Look for cracks in the harness and corrosion in the connection, first guess on troubleshooting. If you have a meter while apart check if it's getting power from the harness if the above doesn't appear to be the problem.