Cadillac Repair: 91 Cadillac deville, cadillac deville, climate control

Question
My father is giving me a '91 cadillac deville. He acquired it from a friend at his church. Anyway one of the problems it has is it doen't show any of the gauges on the dash. Is this a particular piece on the car or is there a diagnostic I can run to determin the problem? The car also kills the battery regularly so disconnecting the battery is pretty much mandatory; he thinks they are a related problem. Any advise is appreciated.

Answer
Do you have a DIGITAL or ANALOG dash ?.

IS or HAS the CHECK ENGINE light on the dash ever illuminated while driving the car ?.

In the fuel display is there anything showing such as:

-c or -d or -151 or --- or is it totally BLANK ?.

Is the climate control panel working ?. If NOT, unplug the climate control panel wires and see if the dash lights come ON. if they DO, Replace the climate control panel.