Misfire condition. You may need a tune up or have a compression loss.
Not in normal driving.
That depends on when it's blinking. If it's blinking rapidly when you turn the key on, there is a problem in the anti-theft, and the truck probably won't start. If it's blinking every 3 seconds when the key is off, that is a normal condition. It's telling you that the system is armed and ready.
It is blinking because there is a problem with the Antilock Brake System (ABS). Seek professional help. Your normal brakes will still work as they should even though the ABS may not.
No problem
One of the bulbs is burned out on the left side. The left front or rear bulb is burned out. Same problem with left side blinking rapidly and right side blinking normal speed. Both left side bulbs are lighting up, however?? Replaced both anyway and the problem still exists.
NORMAL
No problem
That is normal operation.
A poor earth could be the problem here, or a bulb incorrectly fitted, but also a faulty flasher relay could be held responsible.
I have 2002 Aurora with the same problem.
200k miles is not a problem with normal maintenance.
that is normal I have three fords in my driveway including a 99 Windstar and they all do it. ======================================================== Just adding to the answer ( once the doors are locked )