For 1990-2009 cars
Blower Motors and Actuators
Master Electrical Component List

### Circuit Description

The ambient air temperature sensor provides the HVAC control module software with the temperature of the air outside the vehicle. A reference voltage is supplied to the sensor thermistor and the HVAC control module determines the voltage drop across that device which is proportional to temperature. As the air temperature increases, the resistance decreases. As the air temperature decreases, the resistance increases and the voltage signal increases. The inside air temperature sensor provides the HVAC control module software with the temperature of the air inside the vehicle. A reference voltage is supplied to the sensor thermistor and the HVAC control module determines the voltage drop across that device which is proportional to temperature. As the air temperature increases, the resistance decreases. As the air temperature decreases, the resistance increases and the voltage signal increases.

### Conditions for Running the DTC

1. The ignition is in the RUN position.
2. Any of the conditions for setting the DTC are met for 30 seconds.

### Conditions for Setting the DTC

B0160: The HVAC control module detects the ambient air temperature sensor signal circuit is less than 10 counts for more than 30 seconds.
B0161: The HVAC control module detects the ambient air temperature sensor signal circuit is more than 252 counts for more than 30 seconds.
B0165: The HVAC control module detects the inside air temperature sensor signal circuit is less than 10 counts for more than 30 seconds.
B0166: The HVAC control module detects the inside air temperature sensor signal circuit is more than 252 counts for more than 30 seconds.

### Action Taken When the DTC Sets

B0160 or B0165: The system operates in the maximum cooling mode, except when maximum heating is selected.
B0161 or B0166: The system operates in the maximum heating mode, except when maximum cooling is selected.

### Conditions for Clearing the DTC

• | The DTC will become history if the HVAC control module no longer detects the condition that set the DTC.

• | The history DTC will clear after 40 fault free ignition cycles.

• | The DTC can be cleared with a scan tool.

### Diagnostic Aids

• | For inside air temperature problems check the aspirator hose connection on the HVAC control module.

• | If no problem has been found refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

### Test Description

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. The inside air temperature sensor is located inside the HVAC control module. Testing for the inside air temperature sensor will be done through the HVAC control module connector.

4. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens upon performing this test, the signal circuit has a short to voltage.

5. Replacement of the inside air temperature sensor can only be done by replacing the HVAC control module.

Step | Action | Values | Yes | No
--- | --- | --- | --- | ---
Connector End View Reference: HVAC Connector End Views
1 | Did you perform the HVAC control module Diagnostic System Check? | -- | Go to Step 2 | Go to Diagnostic System Check - HVAC Systems - Automatic
2 |

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With a scan tool, observe the Outside Air and Passenger Compartment Temperature parameters in the actuator data list for the HVAC control module.

Does the scan tool indicate that the Outside Air and Passenger Compartment Temperature parameters are within the specified range?

10 - 252 counts

Go to Diagnostic Aids

Go to Step 3

3 |

1. Turn OFF the ignition.
2. Disconnect the Inside Air Temperature sensor circuit at the HVAC control module. Reconnect the HVAC connector.
3. Disconnect the ambient air temperature sensor.
4. Turn ON the ignition, with the engine OFF.
5. With a scan tool, observe the Outside Air and Passenger Compartment Temperature parameter.

Does the scan tool indicate the Outside Air Temp or the Passenger Compartment Air Temp parameter is greater than the specified value?

252 counts

Go to Step 4

Go to Step 5

4 |

1. Turn OFF the ignition.
2. Connect a 3-ampere fused jumper wire between the signal circuit of the ambient air temperature sensor or the inside air temperature sensor and the low reference circuit of the ambient air temperature or the inside air temperature sensor.
3. Turn ON the ignition, with the engine OFF.
4. With a scan tool, observe the Outside Air and Passenger Compartment Air Temperature parameters.

Is the scan tool Outside Air and Passenger Compartment Temperature parameters less than the specified value?

10 counts

Go to Step 8

Go to Step 6

5 | Test the signal circuit of the Inside Air or Ambient Air Temperature sensor for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 12 | Go to Step 9
6 | Test the signal circuit of the Inside Air or Ambient Air Temperature sensor for one of the following conditions:

• | A short to voltage

• | A high resistance

• | An open

Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 7

7 | Test the low reference circuit of the Inside Air or Ambient Air Temperature sensor for one of the following conditions:

• | A high resistance

• | An open

Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 12

Go to Step 9

8 | Test the signal circuits of the following components for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems:

• | Sunload Sensor

• | Inside Air Temperature Sensor

• | Evaporator Temperature Sensor

Did you find and correct the condition?

--

Go to Step 13

Go to Step 10

9 | Inspect for poor connections at the harness connector of the Ambient Air or Inside Air Temperature sensor. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 11
10 | Inspect for poor connections at the harness connector of the HVAC control module. Refer to Testing for Intermittent Conditions and Poor Connections and to Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 13 | Go to Step 12
11 | Replace the ambient air or inside air temperature sensor. Refer to Ambient Air Temperature Sensor Replacement in Wiring Systems or HVAC Control Module Replacement . Did you complete the replacement? | -- | Go to Step 13 | --
12 | Replace the HVAC control module. Refer to HVAC Control Module Replacement . Did you complete the replacement? | -- | Go to Step 13 | --
13 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC.

Does the DTC reset?

--

Go to Step 2

System OK