1. Abnormal sound of the windows
This failure may be caused by loose screws of the window lifter. Tightening the screws will fix the problem.

2. Stuck window lifter
This failure may be caused by deformation or damage of the window groove, loose screws of the window lifter, deviation of the guide rails from their intended installation position, or damage of the window lifter. This problem is mainly fixed by cleaning/replace the window groove or loosen the window screws to adjust the window.

3. Malfunction of all window lifters
This failure may be caused by fall-off of the earth wire of the combination switch, fall-off of the general power line, poor contact or damage of the relay, or poor contact or failed closing of the locking switch. The corresponding circuits should be inspected and repaired.