B0185

DTC B0185

CIRCUIT DESCRIPTION




- B0185 solar load sensor circuit low - short to ground on signal circuit.
- B0186 solar load sensor circuit high - short to voltage or open on low reference or signal circuit.

The ambient light sensor is a 2-wire photo diode. Low reference and signal circuits enable the sensor to operate. As the sunload increases, the sensor signal decreases. The sensor operates within an intensity range between completely dark and bright. The sensor signal varies between 0-5 volts. The HVAC control module converts the signal to a range between 0-255 counts. The ambient light sensor provides the HVAC control module a measurement of the amount of light shining on the vehicle. Bright, or high intensity, light causes the vehicles inside temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.

CONDITIONS FOR RUNNING THE DTC
- The ignition is in the RUN position.
- Any of the conditions for setting the DTC are met for 60 seconds.

CONDITIONS FOR SETTING THE DTC
The HVAC control module detects the signal circuit is less than 0.09 volts (6 counts) or more than 4.90-5 volts (251 counts).

ACTION TAKEN WHEN THE DTC SETS
- If the DTC sets due to a low voltage condition, the HVAC control module will operate the system as if a maximum sunload condition exists.
- If the DTC sets due to a high voltage condition, the HVAC control module will operate the system as if a minimum sunload condition exists.

CONDITIONS FOR CLEARING THE DTC
- The DTC will become history if the HVAC control module no longer detects a failure.
- The history DTC will clear after 40-fault free ignition cycles.
- The DTC can be cleared with a scan tool.

TEST DESCRIPTION

Steps 1-10:

Steps 11-13:

The numbers below refer to the step numbers on the diagnostic table.
3. Tests for the proper operation of the circuit in the high voltage range.
4. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.