See also the related forms, Sidney (English and French), Sidney (English and French). Dennis is a classic favorite. Today it is still a fairly popular baby name for boys, though not to the extent it was in the past. Its usage peaked in 1946 with 1.299% of baby boys being given the name Dennis.
When we use the turn signal switch, it cancels the brake light signal, on the side selected. If it did not, the lights would stay on and not flash. A bad turn-signal switch may interrupt the brake light circuit when it should not. A broken wire to or from the switch may also cause the lower brake-lights not to work. The third brake light does not flash with turn signals.
The reason the light trips the light in your current configuration is that CFL lights take a lot of energy to start up. This energy takes the form of a spike, which can cause the power going through the conductors to be imbalanced for a tiny fraction of a second. GFCI devices are designed to trip if they see an imbalance. The reason it doesn't always trip is that there is a delay between when the GFCI device first sees this imbalance, and when it trips. If it didn't, just about everything more complex than an incandescent light bulb would trip them.