The power for right turn and left turn signals comes from the turn signal, and will only be there on brake and turn signal. The power for the tail lights comes from the light switch. IF you bypass the turn signal switch, no blinking, turn signal. I have seen the turn signals go bad because of too many amp draw or bad ground on the rear lights. The turn signal contact posts with too many amps on them will over heat and move out of position, no contact. That does not account for the tail lights which are on the light switch. I suggest you use a VOM or test light and trace back from the firewall connector.

Larry

I don't own a vehicle that isn't old enough to drink.