tail lights on a '97 Aurora

My back running lights are not working at all. Brake lamps and turning signal lamps work fine. I checked the fuses and I tried new bulbs. Looks like it may be an electrical issue but I wanted to see if there was anything else I could try that I don't know about, before I take it to the shop.
Thanks in advance.

If you have one of those $2.00 test lights, you can check to see if you have power in your bulb socket.

there's a good chance that it's a headlamp control module. This is a black box directly under the dash on the drivers side by the steering column. I had the pleasure:banghead: of finding this out after I replaced the headlight switch which goes for almost 200+. Now everything is perfect.