My Truck was built on a fri or mon morning...lol....No led blinkers, Just factory bulbs, But as mech told me, I have the old style lights......wtf ???? All blinkers work as they should outside the vehicle, On the cluster my left turn is doing 9000 rpm and the right blinks normal,,,,Its only the left on the cluster only....Help....Its annoying

 

Suggest you look VERY CAREFULLY at the lights, both front and rear when the left turn is selected.

One of them , either front or rear is using the parking light element of the bulb instead of the signal light element.

 

Crazy Truck I have....napa, pepboys, and another all gave me the wrong bulbs.....My ford only had front blinker bulb, which is a very small bulb....Tomorrow the rear bulb will be in.....I can say ford was kinda confused the left blinker on cluster is going way to fast and the blinker it self blinks normal in housing....

 

Can you consider this,
In your owner's manual, it should list which bulbs for what.

That should help prevent getting and installing the incorrect bulbs. Not saying an incorrect bulb was installed, but you would be surprised how some people can get a wrong bulb in the right place. I couldn't get it in there if I tried , lol.

 

Very true with owners manual....But I'm 59, I've never had an issue with getting a darn bulb....Its a bulb....lol.... I bought it new, never replaced them before. Kinda my fault, ford is 15 miles away, 3 parts stores 4 miles away? so go grab 2 bulbs.........I should of drove 15 miles

 

Everybody thinks all bulbs are made in the USA, but they are not.. Check before you buy.
Lots of cheap junk out there.


They copy the original packaging, so it can be difficult to tell. Now you know to check.

 

Well new bulb finally came in....No help at all................Back to the drawing board....

 

Can you try this,
turn 4 way flashers on,
look carefully at the lights in front and rear,. What we are looking for is do both front signal lamps shine with the same intensity? If they appear the same, then compare the rear lamps for equal brightness. One of them, on the left side, has to appear dimmer than the others and that is the one with the bad ground connection. It could be the bulb socket or where the socket gets its ground connection.
You tried the easy part, now you have to go a little further. You can do this !

 

Very first thing, find out how many flasher relay your truck has, it can be one or two or three.
2nd thing, disconnect the connector of your left blinker, jump a 12v and a ground wire directly to the connector to illuminate your blinker, this will tell you if your bulb is still good or not.
With a flasher relay you can blink your brake your reverse light or your fog light, without a flasher relay (testing your blinker) there is no pulse and the light stays on. If it blinks fast that means your bulb is good, if it was bad it wouldn't even blink, it's the connection, the wiring from that particular flasher relay to your left blinker having issue, or even the flasher relay itself if yours has a dedicated flasher relay for the left.

 

I gave up......sooooooooooooooo, my beautiful color matched Truck some how backed into a pole.....600 to fix, or new for 700.......700 it is.....unhooked both batteries did the new bumper my self.....shoot me now.......after market bumper all black with lights.....looks sweet.....what to do with the front wht bumper now.....lol......Started truck to move.....Dont you know my left blinker on dash now blinks normal .......Unreal.....why didn't I start with the batterie's ????????????? But hey,,,,,Thanks guys for the input.......Im sure my truck was built on a fri ......lol