a question on brake lights.

If I may,
Never use those crimp on connectors, they suck. (can't trust em and they corrode)
As Grassy stated in his comment LED's don't have enough amp load to make a thermal flasher work, and an electronic flasher will keep working even if some or ALL the bulbs don't work (incandescant or LED either one)

Bill is right on the nose with not using load resistors, as they are a waste of time, money, and amps.
One of the reasons we change to LED's is to lessen the amp load on the system, and load resistors make using LED's pointless if they add a load to make the flasher work.

Grassy, notice where in the specs of that flasher it says "Thermal Flasher"?
That's not it.
Solid state and electronic are different things.

Napa part number Signal Stat 262 or equivalent is what you want.