Denny is right. I have LED's on my flatbed AND there is not enough current draw. My flashers flash fast all of the time. I have searched high and low for a replacement flasher. None to be found, dealer item only. I ran a resistor pigtail for a while that plugged into my trailer plug, but the vibration kept getting to it. Hey it was a $2 experiment, not a permanent fix. A resistor in the wiring done properly would cure the problem, but I would much rather have a bombed flasher. The resistor defeats some of the purpose of the LED's because it adds load to the system. My knowledge of electronics is somewhat limited, but there must be a way to bomb the stock flasher to get rid of the current sensing portion of the circuit???
Grote does make a LED flasher, but not for the newer 5 terminals like we have. Maybe in time and with enough requests they will.