I have a 2014 ford focus were the brake lamp bulb fault message flashes across the screen. The bulb was changed and now the message is there again. Dropped car off at the dealer that found nothing.

SOURCE: focus brake light fault

Is this the same light for the emergency brake?

SOURCE: ford focus

only one light not working indicates a bad circuit at the plug on the back of the light housing or in the wiring between the light and the dash swith

SOURCE: ford focus brake lamp failure switch

Yes. All three brake lights are out and it not a fuse problem. It is not a bulb problem.

SOURCE: Ford Focus Engine System Fault warning light

yes there is a know problem with the fuel system. fuel pump breaks down, empty your fuel filter into a bowl and check for metalic, if you have this in the filter your pump is F..... along with all the other common rail stuff. expensive job... error codes though, i find that hard to believe, fuel pressure faults will occur, i think you garage does not know what to do. or does not want to tell you the cost of the job and he will be in doubt himself of wether he is right..... was you engine coil light flashing at any point.!!!

SOURCE: how do you change rear brake light bulb in a Ford

You will need to look in trunk and pull back the covering over the light area on the side you need to replace. Once exposed, look for the wires going into the light housing and twist the plug to unlock it and remove the bulb. Twist and remove the old bulb or Pull the bulb out of the socket. Reverse the process to install the new bulb and replace the socket.