Pinpoint Test B: The Outside Air Temperature Is Inaccurate/Inoperative
Electronic Compass
Pinpoint Tests
Pinpoint Test B: The Outside Air Temperature Is Inaccurate/Inoperative
Refer to Wiring Diagram Set 102, Overhead Console for schematic and connector information. Diagrams By Number
Normal Operation
The compass and ambient air temperature display can be turned on and off by pressing the SELECT switch in the overhead console.
The temperature can be displayed in Celsius or Fahrenheit by pressing the SELECT switch.
The ambient air temperature display receives temperature input from the ambient air temperature sensor through circuits VH407 (YE/GN) and RH107 (GN/BU). If the circuits are shorted or open, then the display shows 60°C (140°F) (shorted), or -40°C (-40°F) (open).
The ambient air temperature display receives voltage from the Smart Junction Box (SJB) fuse 43 (10A) through circuit CBP43 (GY). Ground for the ambient air temperature display is provided by circuit GD126 (BK/WH).
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- Ambient air temperature sensor
- Compass and ambient air temperature display
PINPOINT TEST B: THE OUTSIDE AIR TEMPERATURE IS INACCURATE/INOPERATIVE
NOTE: After installing a new compass display, always set the zone and calibrate.
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B1 CHECK FOR A CORRECTLY INSTALLED AMBIENT AIR TEMPERATURE SENSOR
- Ignition OFF.
- Verify the ambient air temperature sensor is correctly installed and fully connected.
- Is the ambient air temperature sensor correctly installed and fully connected?
Yes
GO to B2.
No
REINSTALL or RECONNECT the ambient air temperature sensor. TEST the system for normal operation.
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B2 CHECK THE AMBIENT AIR TEMPERATURE SENSOR FUNCTION
- Disconnect: Ambient Air Temperature Sensor C132.
- Remove the ambient air temperature sensor.
- Measure the resistance between the ambient air temperature sensor pins, component side, at an ambient temperature of 18-29.5°C (65-85°F).
- Is the resistance between 8,000 and 14,000 ohms?
Yes
GO to B3.
No
INSTALL a new ambient air temperature sensor. TEST the system for normal operation.
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B3 CHECK THE AMBIENT AIR TEMPERATURE SENSOR CIRCUIT FEED FOR AN OPEN
- Disconnect: Overhead Console C930.
- Measure the resistance between the overhead console C930-5, circuit VH407 (YE/GN), harness side and the ambient air temperature sensor C132-1, circuit VH407 (YE/GN), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to B4.
No
REPAIR the circuit. TEST the system for normal operation.
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B4 CHECK THE AMBIENT AIR TEMPERATURE SENSOR CIRCUIT RETURN FOR AN OPEN
- Measure the resistance between the overhead console C930-6, circuit RH107 (GN/BU), harness side and the ambient air temperature sensor C132-2, circuit RH107 (GN/BU), harness side.
- Is the resistance less than 5 ohms?
Yes
GO to B5.
No
REPAIR the circuit. TEST the system for normal operation.
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B5 CHECK THE AMBIENT AIR TEMPERATURE SENSOR CIRCUITS FOR A SHORT TOGETHER
- Measure the resistance between the ambient air temperature sensor C132-1, circuit VH407 (YE/GN), harness side and the ambient air temperature sensor C132-2, circuit RH107 (GN/BU), harness side.
- Is the resistance greater than 10,000 ohms?
Yes
GO to B6.
No
REPAIR the circuits. TEST the system for normal operation.
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B6 CHECK THE AMBIENT AIR TEMPERATURE SENSOR CIRCUITS FOR A SHORT TO GROUND
- Measure the resistance between the ambient air temperature sensor C132-1, circuit VH407 (YE/GN), harness side and ground; and between the ambient air temperature sensor C132-2, circuit RH107 (GN/BU), harness side and ground.
- Are the resistances greater than 10,000 ohms?
Yes
GO to B7.
No
REPAIR the circuit in question. TEST the system for normal operation.
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B7 CHECK THE AMBIENT AIR TEMPERATURE SENSOR CIRCUITS FOR A SHORT TO VOLTAGE
- Ignition ON.
- Measure the voltage between the ambient air temperature sensor C132-1, circuit VH407 (YE/GN), harness side and ground; and between the ambient air temperature sensor C132-2, circuit RH107 (GN/BU), harness side and ground.
- Is any voltage present?
Yes
REPAIR the circuit in question. TEST the system for normal operation.
No
INSTALL the original ambient air temperature sensor. CONNECT the ambient air temperature sensor. GO to B8.
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B8 CHECK THE TEMPERATURE ACCURACY
- Connect: Overhead Console C930.
- Drive the vehicle for 3 minutes above 56 km/h (35 mph) (sustained).
- Does the display show the correct ambient air temperature using a thermometer for a comparison?
Yes
The ambient air temperature function is OK. REVIEW the operation of the ambient air temperature display with the customer.
No
INSTALL a new compass display (overhead console). REFER to Compass Display Service and Repair. TEST the system for normal operation.
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