Circuit/System Testing

Ignition OFF, all vehicle systems OFF, disconnect the connector at the B117A Windshield Outside Moisture/Ambient Light and Humidity Sensor. It may take up to 2 min for all vehicle systems to power down.
Test for less than 10 Ω between the ground circuit terminal 3 and ground.
- If 10 Ω or greater
  Repair the open/high resistance in circuit 2351 or ground connection.
- Go to next step: If less than 10 Ω
Ignition ON, verify a test lamp illuminates between the B+ circuit terminal 1 and ground.
- If the test lamp does not illuminate and the circuit fuse is good
1. Test circuit 4540 for an open/high resistance.
  - If an open/high resistance is found, repair the fault on the circuit.
  - Go to next step: If an open/high resistance is not found.
2. Refer to Retained Accessory Power Malfunction
- If the test lamp does not illuminate and the circuit fuse is open
1. Test circuit 4540 for a short to ground.
  - If a short to ground is found, repair the fault on the circuit.
  - Go to next step: If a short to ground is not found.
2. Replace the B117A Windshield Outside Moisture/Ambient Light and Humidity Sensor.
- Go to next step: If the test lamp illuminates
Ignition OFF, remove the test lamp, ignition ON.
Test for 5 - 10 V between the serial data circuit terminal 2 and ground.
- If not 5 - 10 V
  Refer to DTC U1500-U15FF
- Go to next step: If between 5.0 - 10.0 V
Replace the B117A Windshield Outside Moisture/Ambient Light and Humidity Sensor.