B160F-11

B160F-11-TWILIGHT/AMBIENT LIGHT SENSOR INPUT - CIRCUIT SHORT TO GROUND





For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The HVAC A/C Heater Control uses a variety of sensors to adjust HVAC operation to obtain optimal performance. These sensors are continuously monitored by the A/C Heater Control to assure that they are in range. If those sensors fall out of predetermined ranges a Diagnostic Trouble Code (DTC) will set. For further information Sun Sensor - Operation

- When Monitored:
With the ignition on.

- Set Condition:
If the Twilight or Ambient Light Sensor input voltage is less than 1.05 volts for period of 1.2 seconds.





Always perform the HVAC Pre-Diagnostic Troubleshooting procedure before proceeding. HVAC Pre-Diagnostic Troubleshooting Procedure.

1. CHECK IF THE DTC IS ACTIVE
1. Ignition on, engine not running.
2. With the scan tool, read HVAC DTCs.

Is this DTC active?

Yes

- Go To 2

No

- Go To 4

2. CHECK (L24) AUTO HEADLAMPS SIGNAL CIRCUIT FOR A SHORT TO GROUND




1. Turn the ignition off to the lock position.
2. Disconnect the A/C Heater Control C1 harness connector.
3. Disconnect the Sun Sensor harness connector.
4. Measure the resistance between ground and the (L24) Auto Headlamps Signal circuit.

Is the resistance below 100k Ohms?

Yes

- Repair the (L24) Auto Headlamps Signal circuit for a short to ground.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Go To 3

3. CHECK THE SUN SENSOR AND A/C HEATER CONTROL
1. Replace the Sun Sensor. Sun Sensor - Removal.
2. Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

Did this DTC reset while performing the HVAC Verification Test?

Yes

- Replace and program the A/C Heater Control. A/C And Heater Control - Removal.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Test complete.

4. CHECK THE WIRING AND CONNECTORS
1. The conditions necessary to set the DTC are not present at this time.
2. With the scan tool, check the Environmental Data to help identify the conditions in which the DTC was set.
3. Using the wiring diagrams as a guide, check all related splices and connectors for signs of water intrusion, corrosion, pushed out or bent terminals, and correct pin tension.
4. Wiggle the wiring and connectors while checking for shorted and open circuits.

Were there any problems found?

Yes

- Repair as necessary.
- Perform the HVAC VERIFICATION TEST. HVAC Verification Test.

No

- Test complete.