Compass/Temperature Mirror

The optional Compass/Temperature Mirror has a vacuum fluorescent (VF) display that is integrated into the rear view mirror. The Compass/Temp Mirror includes the compass/temperature display and two map/reading lamps. This display provides the outside temperature and one of eight compass headings to indicate the direction the vehicle is facing. The Compass/Temp Mirror displays the compass heading and the outside temperature at the same time. The Ambient Temperature Sensor monitors the outside temperature and is hardwired to the PCM. The Compass/Temp Mirror also receives and transmits data on the PCI Bus.

The Compass/Temp Mirror incorporates 2 reading lamp buttons with the STEP button and the Zone/Calibration button features activated by holding a button for a specified time period. The STEP button provides the selections between English and Metric. The Zone/Cal button provides the selection to change the compass zone or to calibrate the compass. The reading lamp buttons also cycle the reading lamps on or off.

The STEP button (right reading lamp button) operates a momentary contact switch which provides input to the Compass/Temp Mirror in one of the following four modes:
- To toggle the right reading lamp on and off upon release of the button.
- To select degrees in F (Fahrenheit) for the temperature display.
- To select degrees in C (Celsius) for the temperature display.
- To turn off the compass/temperature display.

ENGLISH/METRIC/OFF MODE
With the ignition in the ON position, pressing and holding the STEP button (right reading lamp button) for 5-10 seconds will toggle the display between English and Metric. The Compass/Temp Mirror stores the selected display mode in memory upon releasing the button during the 5-10 seconds.

Pressing and holding the STEP button for 10-15 seconds will turn the display OFF upon releasing the button during the 10-15 seconds.

Each time the temperature mode is changed to F° or C°, the Compass/Temp Mirror stores the new mode in memory. The selected English or Metric mode is recalled after the ignition is cycled. The display OFF mode is not recalled after the ignition is cycled. The Compass/Temp Mirror will power up and display the temperature mode (F° or C°) that was last selected.

CALIBRATION/ZONE MODE




Refer to the Zone Variance Map. With the ignition in the ON position, pressing and holding the Zone/Cal button (left reading lamp button) for 5-10 seconds will illuminate ZONE in the display. Releasing the button while ZONE is illuminated will enter the compass into the Zone Setting mode. The Compass/Temp Mirror will illuminate the Zone Variance number 1 to 15 that is stored in memory. While ZONE is displayed; momentarily pressing the Zone/Cal button advances the zone to the next higher zone. When the desired zone number is displayed, do not press the Zone/Cal button again. After 5 seconds, the Zone Variance number will be stored in the module memory.

With the ignition in the ON position, pressing and holding the Zone/Cal button for 10-15 seconds will toggle the CAL (calibration) mode between on and off. Releasing the button while CAL is displayed enters the compass into the calibration mode. See "First Time Calibration", "Manual Calibration", and "Continuous Calibration." Pressing and holding the Zone/Cal button for 15-20 seconds and then releasing will exit the CAL mode and toggle the display to the current state of compass/temperature mirror use; OFF, Compass/Temperature F°, or Compass/Temperature C°.

Pressing and holding the Zone/Cal button for 20-25 seconds will enter the CTM into the self-check diagnostic mode upon releasing the button.

Holding the Zone/Cal button for longer than 25 seconds will cause the display to return to its current state with no changes.

SETTING COMPASS ZONE
The compass has a default zone of 8. Refer to the Zone Variance Map to determine the correct zone number. The correct compass Zone selection is critical to proper compass operation. With the ignition in the ON position, pressing the Zone/Cal button (left reading lamp button) for 5-10 seconds and then releasing while ZONE is illuminated enters the compass into the Zone display mode. In the Zone display mode, ZONE will be illuminated instead of the temperature. The current Zone number, 1 through 15 will be displayed. While ZONE is illuminated; momentarily pressing the Zone/Cal button advances the zone to the next higher zone. When the desired zone number is displayed, do not press the Zone/Cal button again. After 5 seconds, the Zone Variance number will be stored in the module memory.

FIRST TIME CALIBRATION
A new Compass/Temp Mirror is shipped in a first time calibration mode. CAL is illuminated when the Compass/Temp Mirror is first powered up. The first time calibration mode can not be exited until the first time calibration process is completed. The CAL icon will remain illuminated to alert the driver that the Compass/Temp Mirror is operating in the CAL mode. Move the vehicle to an area away from large metallic objects or overhead power lines. While CAL is illuminated in the display the vehicle must be driven in 3 complete 360 degree circles at less than 5 MPH (8 KPH). The compass will calibrate; CAL will turn off, and then resume normal operation.

MANUAL CALIBRATION
With the ignition in the ON position, pressing and holding the Zone/Cal button (left reading lamp button) for 10-15 seconds will toggle the display to CAL. Releasing the button within the 10-15 second duration will enter the compass into the calibration mode. CAL will remain illuminated until the calibration is complete or is toggled off by pressing the Zone/Cal button. Move the vehicle to an area away from large metallic objects or overhead power lines. While CAL is illuminated in the display the vehicle must be driven in 3 complete 360 degree circles at less than 5 MPH (8 KPH). The compass will calibrate; CAL will turn off, and then resume normal operation.

CONTINUOUS CALIBRATION
During normal operation, the Compass/Temp Mirror will continuously update the compass calibration to adjust for gradual changes in the vehicle's magnetic remnant field. If the vehicle is subjected to high magnetic influences, the compass may appear to indicate false headings or appear unable to be calibrated. If this occurs the vehicle may need to be demagnetized. Refer to Demagnetizing Procedure.

SELF-CHECK DIAGNOSTICS
With the ignition ON, the Compass/Temp Mirror can perform a diagnostic self- check by pressing and holding the Zone/Cal button (left reading lamp button) for 20-25 seconds. The internal diagnostics will sequence the following five tests:
1. VF segment display- Illuminates the segment patterns one at a time for 1 second each as follows: CAL; ZONE; N; NE; E; SE; S; SW; W; NW; 0 through 9; C°; F°
2. CTM memory - ROM Checksum
3. CTM memory - RAM
4. CTM memory - EEPROM
5. Compass Test

During the self-check, if any of the internal tests fail, the Compass/Temp Mirror will display an "F" and the number of the test that failed. If more than one test fails "FO" will be displayed. P-Pass or F-Fail will be displayed until the Zone/Cal button (left reading lamp button) is pressed and released or the ignition is cycled. If all of the tests pass, the Compass/Temp Mirror will display "P". A VF segment that fails to illuminate will not cause the Compass/Temp Mirror to display an "F". If any segment fails to illuminate or the Compass/Temp Mirror displays "F", the Compass/Temp Mirror must be replaced.

To exit self-check diagnostics, press and release the Zone/Cal button or cycle the ignition to return to normal compass/temp operation.

OUTSIDE TEMPERATURE
The Compass/Temp Mirror utilizes vehicle speed and engine temperature data received on the PCI Bus to accurately display the outside temperature to avoid "hot soak" condition readings. The displayed outside temperature information is stored within the memory of the compass/temp mirror. When the Compass/Temp Mirror is first powered up, it retrieves the temperature data from the module memory. The memory temperature is compared with the temperature received from the ambient temperature sensor. The colder of the two temperatures is displayed.

TEMPERATURE UPDATE - WARM
On power up, when the outside temperature sensed by the ambient temperature sensor is warmer than the temperature stored in the module memory, the Compass/Temp Mirror will update the displayed temperature in relation to vehicle speed and engine temperature data received on the PCI Bus.

TEMPERATURE UPDATE - COLD
On power up, when the outside air temperature sensed by the ambient temperature sensor is colder than the stored memory temperature, the Compass/Temp Mirror will update the displayed temperature to the outside temperature at a rate of -1° F every 2 seconds, regardless if the vehicle is moving or not.

EXTREME TEMPERATURE/OPEN OR SHORT CONDITION
If the measured outside temperature is more than 60° C (140° F) or the ambient temperature sensor sense circuit is shorted to ground, the temp display will be 60° C (140° F) to indicate a short circuit condition.

If the measured outside temperature is less than -45° C (-49° F) or the ambient temperature sensor sense circuit is open, the temp display will be -45° C (-49° F) to indicate an open circuit condition.

AMBIENT TEMPERATURE SENSOR
The Ambient Temperature Sensor is hardwired to the PCM. The ambient air temperature is monitored and displayed by the Compass/Temp Mirror.

The ambient temperature sensor cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.

The resistance in the ambient temperature sensor changes as the outside temperature rises or falls. The PCM senses the change in reference voltage through the ambient temperature sensor resistor. Based on the resistance of the ambient temperature sensor, the PCM is programmed to correspond to a specific temperature. The Compass/Temp Mirror then displays the proper ambient temperature.

AMBIENT TEMPERATURE SENSOR DIAGNOSTICS
The outside temperature function is supported by the ambient temperature sensor, a signal and ground circuit hardwired to the PCM and the Compass/Temp Mirror display.

If the Compass/Temp Mirror display indicates 60° C (140° F) or the ambient temperature sensor sense circuit is shorted to ground, the temp display will be 60° C (140° F) to indicate a SHORT circuit condition.

If the Compass/Temp Mirror display indicates -45° C (-49° F) or the ambient temperature sensor sense circuit is open, the temp display will be -45° C (-49° F) to indicate an OPEN circuit condition.

If there is an OPEN or SHORT circuit condition, it must be repaired before the Compass/Temp Mirror VF display can be tested.
The ambient temperature sensor can be diagnosed using the following Sensor Test. If there are no codes stored in the PCM and the ambient temperature sensor and the circuits are confirmed to be OK, but the temperature display is inoperative or incorrect, replace the Compass/Temp Mirror.

AMBIENT TEMPERATURE SENSOR TEST
1. Turn the ignition OFF.
2. Disconnect and isolate the battery negative cable.
3. Disconnect the ambient temperature sensor harness connector.
4. Measure the resistance of the ambient temperature sensor using the following values:
- 0° C (32° F) Sensor Resistance = 29.33 - 35.99 Kilohms
- 10° C (50° F) Sensor Resistance = 17.99 - 21.81 Kilohms
- 20° C (68° F) Sensor Resistance = 11.37 - 13.61 Kilohms
- 25° C (77° F) Sensor Resistance = 9.12 - 10.86 Kilohms
- 30° C (86° F) Sensor Resistance = 7.37 - 8.75 Kilohms
- 40° C (104° F) Sensor Resistance = 4.90 - 5.75 Kilohms

The sensor resistance should read between these min/max values. If the resistance value is OK, refer to the Wiring Diagrams to test the Signal and Ground circuits. If the resistance values are not OK, replace the Sensor.