My 1997 Buick Century Limited, the digital temperature display does not show interior, exterior temperature, nor whether it is blowing on the windshield, floor, etc. How do you get it to work, unit works fine other than that. Does the bulb need replaced?

As far as i know-no bulb for digital readout on that one. sounds like control head is bad... check fuses etc. also looking at a diagram loooks like display power runs through the headlight switch? seems odd but a place to look. most likely head though try used or in dewitt ny there is a place called united radio that fixes-rebuilds these look em up i use them from time to time