We have a ceiling fan that includes a light fixture. One day the light went off several minutes after turning it on. I checked the panel, and found that the breakers were ok. Room receptacles from the same breaker are ok too. After shaking the fan wire in the attic, it started working again, but after a couple of hours the same thing happened. I took the fan out and searched for a loose connection, but didn't find one. I traced the wire to a box, where there are four wires coming in. I checked all the wires but no power. Funny thing is the breaker is not tripping.