I have a 1999 f150 xlt 4wd with 5.6. The turn signal started flashing twice as fast as usual only left side. I looked outside and the front left is the same speed as the interior indicator but the rear left has no flashing. Is this an indication of the bulb burned out?

 

yes indeed

 

I checked it out on the week end and you were correct. Lamp burned out. Thanks so much for your responds.

 

That's what mine is doing. Just checked it, left rear bulb is out. Thanks guys!