What would cause dashlights and tail lights on a 1994 Saturn not to work?

There can be several possible causes for instrument panel lights and tail lights to not work. I'm not sure I can recall all of them at the moment but will provide what I can. On most vehicles, the multiposition headlight switch controls [turns ON/OFF] the headlights, front "parking" lights, tail lights, side marker lights, instrument panel lights, and the "dome" and interior courtesy lights. Additionally, on most vehicles, when the the parking and/or headlights are ON, rotation of the headlight switch knob controls the brightness of the instrument lights, and rotated fully counterclockwise turns ON the dome and courtesy lights. Your question mentions the tail lights and the instrument panel lights being non-functional, but not whether or not the headlights, front parking lights, and side marker lights are working. Possible causes of these lights not working could include: 1. A failed fuse, but only if all the other lights you did not mention are also not working. If the fuse is good and all the OTHER lights controlled by the headlight switch are working, then the problem IS "downstream of the headlight switch. 2. A ground wire or wires not properly connected, or having an accumulation of corrosion at the connection interface. 3. A cut or broken wire in the part of the circuit which serves the non-working lights. 4. A connector or connectiors which have come apart, or have an accumulation of corrosion on their contact surfaces. 5. A defective headlight switch, or connector to that switch. There are probably some other causes which I'v left out, but these are the most commonly occuring. The procedure to correct this problem is to first visually check out [via tracing the wires leaving the headlight switch to the non-working lights] all the items I've discussed, looking for anything visually "not normal." It that produces no reason for the failure, then my next step would be to physically disconnect, and reconnect all connectors in the non-working circuit, carefully examining all of the metal contacts within each connector for signs of corrosion [remove if found] or signs of overheating [discoloration]. Either of these could cause the described problem. During this trace and examine process, also look for wires which have been cut, broken, or pulled apart. If all of these checks fail to find any cause, my next step would be to remove the wiring harness connector to the headlight switch, and remove the switch from the instrument panel for inspection and testing. First inspect the switch body and connectors for signs of corrosion or overheating [discoloration]. If corrosion is present, clean the terminal blades on the switch, and the contacts inside the harness connector. If the switch body looks "cooked" it is probably ruined and requires replacement. If the body looks OK, but the terminals look cooked, then with a meter or test light, cycle the switch through all its positions, checking for current flow. If the terminals for the non-working lights does not indicate current flow, then the contact points inside the switch are probably burned and the switch needs to be replaced. Troubleshooting is never an easy process, and the cramped area behind the instrument panel just makes the job more difficult, but it is necessary to check all wires, connectors,fuses, lamp sockets, and grounds. Good luck. j3h.