1990 Cadillac Deville blown fuses

It's possible that your A/C clutch coil has high resistance, or a bad clamping diode in the coil connector is allowing a voltage spike to open the fuse. Does the compressor function(a/c working?)? Not sure why this would happen every couple weeks though. It is possible that a short in the circuit exists. You can try disconnecting the compressor clutch coil, and see if it continues to blow. Pay particular attention to what happens prior to knowing that the fuse has blown, i.E. Trunk opened, seat moved, something that may lead to an area to focus.