Vehicle: 2014 Kia Optima, L4-2.4L, Automatic Transmission/Transaxle

Mileage: 86,989 miles

Problem: The vehicle was brought to the shop to have a bad driver’s front door window regulator replaced. NOTE: A week earlier, one of the techs diagnosed the problem as a bad window regulator because they could hear the motor operating in the door, but the window wouldn’t go up or down. After the work was completed, the window operation was reversed.

Case Details: The owner supplied the shop with a used window regulator assembly that included the motor but not the control module, so the shop swapped out just the control module from the old window regulator assembly.

Once everything was back together, pressing the window switch down made the window move up about one-half inch; pressing up, made the window move down about one-half inch. Pressing to the "Auto" position made no difference.

Based on advice from an ALLDATA Tech-Assist consultant, the technician tested window switch polarity by back probing pins 8 and 9 at the switch (see diagram).

NOTE: With the switch in neutral, the test light should not light. While pressing UP on the switch, pin 8 should light. While pressing DOWN on the switch, Pin 9 should light.

The technician evaluated the switch polarity as advised. The switches operated normally.

Now that they knew the switches were operating correctly, the consultant suggested putting the original control module back on the original motor and reinstalling them on the replacement regulator.

Confirmed Repair: The technician mounted the original control module and motor onto the used window regulator assembly. Once that was done the window operated normally. Fixed!