Electrical Question - Turn Signal SW and Lights

[Noble1221]

I just replaced my turn signal switch in my 71 Blazer. Most all seems to be normal except for one thing.

When I have either left or right directional blinking and I step on the brakes I was expecting both left side and right side lights to get brighter. But only the side opposite the blinking directional side gets brighter?

Anyone know if my expectation is correct and if yes - anyone know how to run thru a troubleshoot from the wires that are in the turn sig switch to the brake lights?