Orlando

DTC B018A, B048C, B048F, or B1395

The windscreen temperature and inside moisture sensor integrates the relative humidity sensor, windscreen temperature sensor and humidity sensing element temperature sensor.

This sensor assembly provides information about:

The relative humidity sensor measures the relative humidity on the compartment side of the windscreen. It also detects the temperature of the windscreen surface on the compartment side. Both values are used as control inputs for the HVAC control module application to calculate the fog risk on windscreen compartment side and ability to reduce fuel consumption by decreasing A/C compressor power to a minimum without causing any fog. The sensor will also enable partial recirculation mode in order to improve heat-up performance of the passenger compartment under cold ambient temperature conditions without the risk of mist build-up on the windscreen. The humidity sensor element temperature sensor supplies the temperature of the humidity sensor element. It is only needed if the thermal contact between the humidity sensing element and the inside windscreen surface is not sufficient.

B018A 02, B048C 02, B048C 02 or B1395 03

The HVAC control module detects the sensor signal out of range. The signal voltage is less than 0.1 V for more than 50 ms.

B018A 05, B048C 05, B048C 05 or B1395 07

The HVAC control module detects the sensor signal out of range. The signal voltage is greater than 4.9 V for more than 50 ms.

The condition for setting the DTC is no longer present.

Schematic Reference

HVAC Schematics : Automatic

Connector End View Reference

Component Connector End Views

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Verify that DTC B1395 03 or B1395 07 is not present.

⇒	If DTC B1395 is present

Refer to Windscreen Temperature And Inside Moisture Sensor Power Supply Malfunction.

⇓	If DTC B1395 is not present

2. Verify that DTC B048C 02 or B048C 05 is not present.

⇒	If DTC B048C is present

Refer to Humidity Sensor Humidity Circuit Malfunction.

⇓	If DTC B048C is not present

3. Verify that DTC B048F 02 or B048F 05 is not present.

⇒	If DTC B048F is present

Refer to Humidity Sensor Temperature Circuit Malfunction.

⇓	If DTC B048F is not present

4. Verify that DTC B018A 02 or B018A 05 is not present.

⇒	If DTC B018A is present

Refer to Windscreen Temperature Sensor Circuit Malfunction.

⇓	If DTC B018A is not present

5. Measure actual temperature using a thermometer at the windscreen temperature and inside moisture sensor. Compare this value to the scan tool Passenger Compartment Humidity Sensor Temperature parameter. The measured temperature should be within 5°C (9°F) difference of parameter value.

⇒	If not within the specified range

Replace the B160 Windscreen Temperature and Inside Moisture Sensor.

⇓	If within the specified range

6. Measure actual temperature using a thermometer at the windscreen temperature and inside moisture sensor. Compare this value to the scan tool Windscreen Temperature parameter. The measured temperature should be within 5°C (9°F) difference of parameter value.

⇒	If not within the specified range

Replace the B160 Windscreen Temperature and Inside Moisture Sensor.

⇓	If within the specified range

7. All OK.

Windscreen Temperature And Inside Moisture Sensor Power Supply Malfunction

1. Ignition OFF, disconnect the harness connector at the B160 Windscreen Temperature and Inside Moisture Sensor.
2. Test for less than 5 Ω between the ground circuit terminal 3 and ground.

⇒	If greater than 5 Ω

Repair the open/high resistance in the circuit.

⇓	If less than 5 Ω

3. Ignition ON, test for 4.8-5.2 V between the ground circuit terminal 3 and the reference voltage circuit terminal 1.

⇒	If less than 4.8 V

3.1.	Ignition OFF, disconnect the X1 harness connector at the K33 HVAC Control Module.

3.2.	Test for infinite resistance between the reference voltage circuit and ground.

⇒	If less than infinite resistance, repair the short to ground on the circuit.

⇓	If infinite resistance

3.3.	Test for less than 2 Ω in the reference voltage circuit end to end.

⇒	If 2 Ω or greater, repair the open/high resistance in the circuit.

⇒	If less than 2 Ω, replace the K33 HVAC Control Module.

⇒	If greater than 5.2 V

3.1.	Ignition OFF, disconnect the X1 harness connector at the K33 HVAC Control Module.

3.2.	Ignition ON, test for less than 0.3 V between the reference voltage circuit and ground.

⇒	If greater than 0.3 V, repair the short to voltage on the circuit.

⇒	If less than 0.3 V, replace the K33 HVAC Control Module.

⇓	If within 4.8-5.2 V

4. Replace the B160 Windscreen Temperature and Inside Moisture Sensor.

Humidity Sensor Humidity Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the B160 Windscreen Temperature and Inside Moisture Sensor.
2. Test for less than 5 Ω between the ground circuit terminal 3 and ground.

⇒	If greater than 5 Ω

Repair the open/high resistance in the circuit.

⇓	If less than 5 Ω

3. Ignition ON, test for 4.8-5.2 V between the ground circuit terminal 3 and the reference voltage circuit terminal 1.

⇒	If less than 4.8 V

3.1.	Ignition OFF, disconnect the X1 harness connector at the K33 HVAC Control Module.

3.2.	Test for infinite resistance between the reference voltage circuit and ground.

⇒	If less than infinite resistance, repair the short to ground on the circuit.

⇓	If infinite resistance

3.3.	Test for less than 2 Ω in the reference voltage circuit end to end.

⇒	If 2 Ω or greater, repair the open/high resistance in the circuit.

⇒	If less than 2 Ω, replace the K33 HVAC Control Module.

⇒	If greater than 5.2 V

3.1.	Ignition OFF, disconnect the X1 harness connector at the K33 HVAC Control Module.

3.2.	Ignition ON, test for less than 0.3 V between the reference voltage circuit and ground.

⇒	If greater than 0.3 V, repair the short to voltage on the circuit.

⇒	If less than 0.3 V, replace the K33 HVAC Control Module.

⇓	If within 4.8-5.2 V

4. Test for 4.8-5.2 V between the signal circuit terminal 2 and ground.

⇒	If less than 4.8 V

4.1.	Ignition OFF, disconnect the X1 harness connector at the K33 HVAC Control Module.

4.2.	Test for infinite resistance between the signal circuit and ground.

⇒	If less than infinite resistance, repair the short to ground on the circuit.

⇓	If infinite resistance

4.3.	Test for less than 2 Ω in the signal circuit end to end.

⇒	If 2 Ω or greater, repair the open/high resistance in the circuit.

⇒	If less than 2 Ω, replace the K33 HVAC Control Module.

⇒	If greater than 5.2 V

4.1.	Ignition OFF, disconnect the X1 harness connector at the K33 HVAC Control Module.

4.2.	Ignition ON, test for less than 0.3 V between the signal circuit and ground.

⇒	If greater than 0.3 V, repair the short to voltage on the circuit.

⇒	If less than 0.3 V, replace the K33 HVAC Control Module.

⇓	If within 4.8-5.2 V

5. Replace the B160 Windscreen Temperature and Inside Moisture Sensor and verify the DTC does not reset.

⇒	If DTC resets

Replace the K33 HVAC Control Module.

⇓	If DTC does not reset

6. All OK.

Humidity Sensor Temperature Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the B160 Windscreen Temperature and Inside Moisture Sensor.
2. Ignition On, test for 4.8-5.2 V between the signal circuit terminal 5 and ground.

⇒	If less than 4.8 V

2.1.	Ignition OFF, disconnect the X1 harness connector at the K33 HVAC Control Module.

2.2.	Test for infinite resistance between the signal circuit and ground.

⇒	If less than infinite resistance, repair the short to ground on the circuit.

⇓	If infinite resistance

2.3.	Test for less than 2 Ω in the signal circuit end to end.

⇒	If 2 Ω or greater, repair the open/high resistance in the circuit.

⇒	If less than 2 Ω, replace the K33 HVAC Control Module.

⇒	If greater than 5.2 V

2.1.	Ignition OFF, disconnect the X1 harness connector at the K33 HVAC Control Module.

2.2.	Ignition ON, test for less than 0.3 V between the signal circuit and ground.

⇒	If greater than 0.3 V, repair the short to voltage on the circuit.

⇒	If less than 0.3 V, replace the K33 HVAC Control Module.

⇓	If within 4.8-5.2 V

3. Replace the B160 Windscreen Temperature and Inside Moisture Sensor and verify the DTC does not reset.

⇒	If DTC resets

Replace the K33 HVAC Control Module.

⇓	If DTC does not reset

4. All OK.

Windscreen Temperature Sensor Circuit Malfunction

1. Ignition OFF, disconnect the harness connector at the B160 Windscreen Temperature and Inside Moisture Sensor.
2. Ignition On, test for 4.8-5.2 V between the signal circuit terminal 4 and ground.

⇒	If less than 4.8 V

2.1.	Ignition OFF, disconnect the X1 harness connector at the K33 HVAC Control Module.

2.2.	Test for infinite resistance between the signal circuit and ground.

⇒	If less than infinite resistance, repair the short to ground on the circuit.

⇓	If infinite resistance

2.3.	Test for less than 2 Ω in the signal circuit end to end.

⇒	If 2 Ω or greater, repair the open/high resistance in the circuit.

⇒	If less than 2 Ω, replace the K33 HVAC Control Module.

⇒	If greater than 5.2 V

2.1.	Ignition OFF, disconnect the X1 harness connector at the K33 HVAC Control Module.

2.2.	Ignition ON, test for less than 0.3 V between the signal circuit and ground.

⇒	If greater than 0.3 V, repair the short to voltage on the circuit.

⇒	If less than 0.3 V, replace the K33 HVAC Control Module.

⇓	If within 4.8-5.2 V

3. Replace the B160 Windscreen Temperature and Inside Moisture Sensor and verify the DTC does not reset.

⇒	If DTC resets

Replace the K33 HVAC Control Module.

⇓	If DTC does not reset

4. All OK.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.