2001 Toyota Sienna 6 cyl Two Wheel Drive Automatic 106k miles

Hi. My driver side view mirror - power/heated, lost its lockiing mechanism. The mirror moves loosely and cannot stay in one position. What happen, per my 16 y/o son was he tried moving the mirror towards the vehicle and heard a popping sound. I took the bottom 3 screws from the housing unit and also from the doors. I could see the ball bearing inside te housing unit of the mirror as well as the 2 plates that locks the mirror together. When I tried pulling the plate that is connected tothe mirror, it seems that the locking mechanism is loose. Here are my questions: Do ineed to change the whole housing unit or can i take it apart and see if i can fix the spring in thte unit. Or, if i need to buy a unit, how do i change it. thank you for your help.

Nope need to replace as unit.