How do you find out why none of your signal lights work on a 93 Cadillac Fleetwood?

To diagnose the non-functioning signal lights on a 1993 Cadillac Fleetwood, start by checking the fuse box for any blown fuses related to the turn signals. Next, inspect the bulbs to ensure they are not burnt out and replace any that are faulty. Additionally, examine the turn signal switch and the wiring for any signs of damage or loose connections. If these steps do not resolve the issue, consider consulting a professional mechanic to further investigate the electrical system.