Title says it all, my blinker is flashing really fast. Now I know what you're gonna say... blown bulb. The front lower driver's side bulb was dead, so I replaced it this weekend (was installing new fog light assemblies as well from deer damage). Now the bulb illuminates just fine when the running lights are on, however if I turn on the left blinker the the bulb turns off and the dash blinker goes double speed as if the bulb was still blown. I checked the tail light blinker and it is blinking double speed so it works, and the right blinker works fine. When I turned on four ways all of the blinkers came on except the driver's front. Not sure where to go from here.

I believe if there was a short the light on the dash would be steady on even if the blinker wasn't turned on. It did do this shortly after I hit the deer, but stopped when I pulled the bulb the first time and put in one from the scrap yard (I was pulling new light assemblies from a near by yard so I could finish the ride home, figured the bulbs would work).

 

I would check out the wiring. My experience tells me, that whenever You have a strange light behavior it is quite often missing (or poor quality of) a ground line.

 

I would double check the new bulb just to make sure it's the correct bulb- never hurts to check the simplest things first.

You could also try swapping the new bulb to the passenger side, and seeing if the symptom follows the bulb over there- indicating a faulty new bulb.

From there, I agree with Mike, it does sound like faulty wiring. Try cleaning the contact points in the bulb socket first, they can corrode and cause a poor connection. If none of that solves it, you'll have to start doing some diagnosis with a voltimeter to find your bad ground or missing power.