well there is a lot of reasons for that matter the turning signal may be left on, you may have left on your caution lights, or if the car has an alarm system it may use the lights to indicate that you have locked or unlocked your vehicle or if you did not lock your vehicle the vehicle may be programed to lock its self after a given amount if time.
Possible headlight switch.
You will have to check all the door sensors.
Yes.
sounds like a bad day and night sensor or bad wiring
probably because you bought a car designed by baboons.
it makes the indicators(the turning lights) blink on and off.
If the '86 is the same as the newer ones, then one of the light switchs on one of the doors has to be replaced.
Check for a bad ground
Need model year and engine info. The Crown Victoria has been around on and off since 1955.
a malfunction has been detected
Faulty head light switch.
electronic short in computer system or a short in a current of the main circuit