Check the Stop Lamp Switch Circuit

Check that stop lamp lights up when brake pedal is depressed and turns off when brake pedal is released.
Measure the voltage between terminal 23 of the ABS control module harness side connector and body ground when brake pedal is depressed.
Specification: approximately B+

Fig 1: Measuring Voltage Between Terminal 23 Of ABS Side Connector And Body Ground
Courtesy of KIA MOTORS AMERICA, INC.
Is the voltage within specification?
YES
- Check the hydraulic circuit for leakage.
NO
- Remedy the stop lamp switch. Remedy an open in the wire between the ABS control module and the stop lamp switch.