Is it the taillights or the brake lights? If taillights it may be a wiring problem, If brake lights check the switch on the brake pedal
check the fuses - there is no fuse for the headlights.
Check the ground wire to the tail lights.
If your referring to tail lights just turn off your headlights and they will turn off. If your referring to break lights take your foot of the break pedal.
Most likely a fuse or a bad ground.
Fuse, wiring, bulbs
First check the bulbs then check the fuses.
Check the bulbs - they are double filamented larger for tailights and smaller for stop/turn Check the fuse for parking/tail and dash lights
I believe you pull the selector knob ( park lights , headlights etc ) towards you
There is a faulty ground wire in one of your tail lights or front parking/clearance lights.
If your car has daytime running lights (standard in Canada) then the only way to turn on just the parking lights is when the car is in park or neutral, the light switch is in the park light position and the parking brake is on. Then the headlights will turn off. Any other configuration means the headlights will be on. On this car, parking lights can truly only be used when parked!
On a 2008 Ford Edge : Turn the park lamps or low beam headlights on and then pull the headlight control towards you to turn on the fog lights
try e brakes..turn the e brakes on and see if it turns off.if it does then you have suto headlights