On my 91 head unit I have a constant loc message. It is a cassette player with a equilizer, in my manual it only has directions for disengaging the cd player with equilizer. Any help would be greatly appreciated. jaynusom@hotmail.com

Is this one of those units where you have to hold the mute button down on the steering wheel?

Try disconnecting and reconnecting the battery a few times. Sometimes it resets the Loc. Well mine did..