This has to be approached very methodically. Start the car, then very carefully start switching on the lights. I usually turn on the parking lights only. Then see if you get the failure. At that point you need to check everything on the parking light circuit, those being the front (clear) parking lights, the front amber side markers in the sides of the front bumper, the rear tail lights and especially BOTH rear license lights, these are often overlooked. Usually it is one of these items. If it isn't those, them turn the headlight switch the next click to check the headlights, them try the high beams and front and rear foglights. Then shut the headlight switch off and step on the brakes. If you get the warning at that point you need to find out which brake light is inop. Also try reverse gear for the backup lights and the turn signals.