Same problem for me with a 2007 Focus LX - rear left indicator bulb not working on indicating or when centrally locking the car, front left blinking twice as fast. Checked fuse (7.5 amps, fuse number 53 according to this diagram: http://www.autogenius.info/ford-focu...e-box-diagram/), fuse fine. By swapping the bulb with the rear right, I proved it wasn't the bulb at fault (i.e. I got the same problem on the rear left with the bulbs swapped, the rear right worked fine). By swapping the bulb holder with the rear-right I proved it WAS the bulb holder at fault (i.e. now the rear-right didn't work and the front right blinked twice as fast). Took the bulb out of the bulb-holder, released the bulb holder from the rest of the assembly by pressing the black release clip and pulling, prised off the inner orange plastic holder inside the bulb holder by using a small-bladed flat head screwdriver to push the three holding clips in at the bottom, then made sure with the small-bladed flat head screwdriver that the contacts were a) pushed down into the holder; b) separated to avoid short circuits; c) springy enough to make contact with the bulb. Then carefully replaced the orange plastic holder, being sure to tuck the vertical electrical connection inside the prescribed place on the side of the orange plastic holder. Tested before re-fitting and it worked. Then re-fitted and re-tested and again it worked. So all I can conclude is there was a loose connection in the bulb holder or the mental connectors were touching in the bulb-holder. Anyway, saved myself a potentially expensive and time-consuming trip to the garage, so thanks for all the advice here that guided me to the solution.