My daughter has a 1995 Crown Victoria. The other day she informed me her left and right turn signals and emergency flashers were not working. They would just stay on (lit) and not blink.
It turns out that 2005 CVs do not use an inexpensive discrete blinker relay, but all the lighting control is via a $ 180.00 LCM "Lighting Control Module". The guy at the auto parts store said I need either the LCM or a new multi-function stalk for the left side of the steering column that controls the turn signals, wipers and several other functions. This is around $70.00
If the lights are working, it is not in the stalk. You can get the LCM rebuilt , as in my case on a '97 P71. Check your fuses under the dash. On rebuilding, I would highly recommend David Ruberg @ speedometerrepairguy.com .