2014 F150 a year old just started intermittently blinking fast and normal on the left turn only. I changed all the lamps out and checked the LED rears. All bulbs blink but it acts like a bulb is out when its not. It blinks fast then normal, like a mind of its own. Any suggestions?

 

Likely A BCM issue. I would get the dealer to look at it. The issue is if it's really intermittent, they can't reproduce and don't fix it AND they will charge you a diagnostic fee.

 

SO WE NOW KNOW THE ISDUE IS TEMPERATURE RELATED. SIGNAL WORKS PERFECT UNTIL THE OUTSIDE TEMP REACHES 78-80 degrees. Then we start having issues. The hotter it gets the worsening gets. Have we narrowed it to A CAUSE?

 

Heat adds resistance, should make the problem go away?


I'd recommend swapping back to OEM incandescent bulbs and see what happens

 

ruled out. We have also noticed it will change once moving or turning ( sometimes ). I'm leaning to one of two things.....BCM or Harness? I'm just not sure how heat would cause either to act up?

 

The system looks for low resistance, since you have swapped bulbs, sounds like maybe several times, I'd start by looking at the pins in the bulb holders