All of these are mechanical failures for a power window EXCEPT:

• A. Broken window regulator
• B. Power window motor electrical fault
• C. Worn sash guide
• D. Poor grounds

Answer: (D)

Power window failures can be mechanical or electrical. Mechanical problems involve parts that physically move the glass: a broken window regulator stops the lift mechanism, and a worn sash guide can cause friction and misalignment that blocks smooth movement. An electrical fault in the motor is not a mechanical failure; it’s an electrical issue that prevents the motor from turning. Likewise, poor grounds are an electrical problem affecting current return rather than a physical moving part. Therefore, the issue that isn’t a mechanical failure is poor grounds.