Circuit/System Testing - With UGN

Ignition OFF, and all vehicle systems OFF, disconnect the harness connector at the S70A Steering Wheel Controls Switch - Left Lower, ignition ON.
Verify a test lamp illuminates when placed between the PWM voltage control terminal 4 and ground.
NOTE:
Verify vehicle interior dimming control is set all the way bright.
- If test lamp does not illuminate
  Refer to Interior Backlighting Malfunction
- If the test lamp illuminates
Connect a test lamp between the control circuit terminal 4 and control circuit terminal 5.
Verify the test lamp turns ON and OFF when commanding the Lane Departure Warning Indicator On and Off with a scan tool.
- If the test lamp is always OFF
1. Ignition OFF, disconnect the harness connector at the K109 Active Safety Control Module.
2. Test for infinite resistance between the voltage circuit and ground.
  - If less than infinite resistance, repair the short to ground in the circuit.
  - If infinite resistance
3. Test for less than 2 Ω in the control circuit end to end.
  - If 2 Ω or greater, repair the open/high resistance in the circuit.
  - If less than 2 Ω, replace the K109 Active Safety Control Module.
- If the test lamp is always ON
1. Ignition OFF, disconnect the harness connector at the K109 Active Safety Control Module, ignition ON.
2. Test for less than 1 V between the voltage circuit and ground.
  - If 1 V or greater, repair the short to voltage on the circuit.
  - If less than 1 V, replace the K109 Active Safety Control Module.
- If the test lamp turns ON and OFF
Test or replace the S70A Steering Wheel Controls Switch - Left Lower.