Ram 2500 4X4 parking lights

2005 ram 2500 4x4 pu all running lights, parking lights, tail lights, license plate, roof lights not working, headlights, turnsignals, flashers all ok, checked all fuses, relays, ok, had a mechanic determine the problem could be the fender control module, had some one else say that is uncommon. Need advice before I drop $500. Thank you