The instrument cluster in my 1993 cadillac seville works intermittently, and sometimes won't come on at all. Any possible solutions other than replacing the entire cluster?

Before it went out I replaced the heater core, having to unplug a few
wires under the passenger side kick plate. Prior to all of this the lights
on the cluster would fade and then come back periodically. None of the
buttons on the cluster works, but the "service engine soon" light will
come on, along with the "brake" and seatbelt lights. Speedometer,
odometer, and gars gauge do not work when it cuts out as well.