[Bill G]

I agree with Rotor wrench. You have to take the output of the brake light switch to the brake light input to the turn signal switch and it then controls which lights or both get the brake light power. The brake lights serve a dual purpose. Brake and turn signal. If the turn signal is not being used at all, both lights would light upon braking. If the left turn signal is being used, the left rear light will blink but not show braking while the right light will indicate braking. Bottom line is that the turn signal switch on the steering column does all the work.