First of all, you say brake and stop - I'm guessing you meant brake and turn?

Brake and turn are both same brightness so not surprising those work. Just guessing here - I think the LED's need to be designed for the 2 different levels of light. I suspect the LED tails have 2 sets of LED's - 1 for parking, that remains on, the other for brake and turn. I know the taillights are designed to work for both stop/turn, your "little lights" may not be. Don't know how you've wired them so not sure what might be happening. Something to look into until someone more knowledgeable chimes in.

I'm watching this because I get mine back from the painter in a few days and begin to rewire, and I'm using LED's all around.

'69 1/2T stepside, Sea Foam Green, 250 L6 w/ 3 on the tree, not an option on it, in the family since new.