2012 F150 XLT Supercrew...

Got in it today and hit my turn signal to go left and it's beating double time. Right signal clicks at roughly once a second, left signal is clicking at 2-3 a second. Got out, check front and back, driver side mirror, to see if I had a bulb out - nope, everything's illuminating correctly. Tried the old IT trick - turn it off and turn it back on - had no effect. Left signal is still triple the speed of the right.

Any thoughts as to what's causing this problem ?

 

Sounds like the wrong bulb was put in. The lack of resistance will cause it. Double check and make sure all bulbs are the same number.

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[QUOTE=Rnlcomp;3279978]Sounds like the wrong bulb was put in. The lack of resistance will cause it. Double check and make sure all bulbs are the same number.

That'd be a really good guess, but I've had this truck close to two years yet and have never replaced any bulb, inside or out. Nor has any repairman.

 

Everything illuminated correctly as in, the bulb lights with the running light circuit then blinks brighter with the turn signal, correct? It may seem like a dumb question; but it needs to be confirmed.

Do you have any aftermarket lighting added like a tailgate bar?

EDIT: Also, turning the truck off and back on with the key most likely wouldn't help...you'd want to disconnect a battery terminal to reset the computer.

 

also, 3 bulbs.. 1 front and 2 rear... top/bottom....mine did this when i painted taillights.. didn't know till i went to use them that i damaged 1 bulb..

 

Steve Osborne, a cigar and cold beer your way. It appears the top bulb in the left rear light assembly isn't illuminating with the same intensity as the bottom bulb. Am guessing that a replacement is in order. Thanks.