electrical trouble 1970 GTO
No power to: Gas gauge, instrument lights, blower motor
none of these circuits are in common with one another. Doubt if you know there is no power to gas gauge. Gauge not working is not a power issue usually. Dash? lights or do you mean instrument idiot? lights? Dash are usually ground issues. Blower motor varies if AC or non AC. Look in factory service manual for first hand info. Best source of detail. Then from there can better answer any questions. Need more detail on each item.