the Voltage limiter is replaceable, they tend to run around $35, i found a more modern replacement on ebay for $25.

typically you have to unscrew the cluster and pull it out enough to remove limiter and put new one in.

Key buzzer is usually a little yellow rectangle box (fits in your palm) and it's usually mounted above the drivers side kick panel into the body with a wide wiring connector plugged into it. might be missing or you have a bad connection.