I own a gen2, last month the power window has occurred problem(driver's side). I already checked the motor, still in good condition(can up and down using optional battery). However, after checked with multimeter, the power supply for the window to up is less than +11V. The window can goes down but can not up (the voltage to window goes down is -14V). It seems like the voltage is not enough for the window to goes up. How can I solve this problem?