Rear right side backing up and turn signal lamps are out.

What is your question?

Changing the lamps did not help. A regular mechanic looked at it and said that it might be that the circuit board that the bulbs go into is bad, OR that the control module is bad and is not activating the lights. Worse case, if it's the SAM module, what range of costs am I looking at? And how do you tell if it IS something more minor, (such as the circuit board,) or the entire SAM module?