NOTE: The switch location of the parking and back-up sensor switch (A) is different depending on the model.
1.
Check the parking and back-up sensor switch according to the table.
NOTE:
When an LED is located between terminals, check if the LED illuminates by connecting power and ground to the LED.
Note this important operating characteristic; diode bias causes a diode to fully conduct electricity in one direction (forward), while not at all in the opposite direction (reverse).