The Fiesta is one of Ford's biggest sellers across America and Europe. However, a common problem that Fiesta drivers face is their rear lights not working.
The most likely cause is a blown bulb. Check the car manual for the type of bulb required and then purchase a new bulb from any auto shop, supermarket or petrol station.
If you have established that the bulb is not the issue, check the fuses. The fuses are located under the steering column on most Fiestas. However, check your car manual for the location and correct replacement fuse.
If it is neither the bulb nor the fuse, the likelihood is that it is a mechanical or electrical problem. If this is the case, contact a professional for diagnosis. It could be a number of things ranging from a loose connection to faulty battery or alternator.
Do not take a guess if you can't solve the problem yourself. Faulty rear lights could be a symptom of a more serious problem.