Rearview Mirror
STANDARD PROCEDURE - REARVIEW MIRRORCompass Calibration
When the compass is subjected to excessive magnetic fields, the EMTM automatically enters a fast calibration mode where it tries to compensate for the large magnetic shifts. Manual activation of the fast calibration mode is usually not required.
If the compass is inaccurate or appears to be inaccurate, the fast calibration mode may be manually entered by using the following procedure:
1. Set the EMTM to Compass/Temperature mode and press the reset button (right lamp button) for 10 seconds.
2. The compass variance defaults to 8 after the fast calibration is manually activated.
3. Complete the compass variance setting procedure by referring to the Compass Variance Procedure.
4. Drive the vehicle in three 360 ° turns in an area free of large metal objects. If the CAL symbol remains lit after completing this step, the roof panel may need to be demagnetized.
Fig. 6 Variance Settings:
Compass Variance Setting Procedure
Variance is the difference between magnetic north and geographic north. To adjust the compass variance, set the EMTM to Compass/Temperature mode and press the center button for five seconds. The symbol VAR and the current variance zone number Will be displayed. Press the step button (center button) to select the proper variance zone as shown in. Once the proper zone has been selected, wait three seconds and the display will return to normal operation. If the center button is held for 10 seconds instead of 5 seconds, the EMTM will set the variance to 8 and enter the fast calibration mode.
Demagnetizing Procedure
A magnetic field can adversely affect the compass. Magnetic interference can magnetize the roof panel. Magnetizing can be caused by placing a permanent magnet in contact with the roof panel.
Examples:
- Magnetic base antenna
- Magnetic screwdriver
- Audio speakers
- Refrigerator magnets
- Pizza signs
- Bubble gum flasher lights
Removing magnetic interfering objects will usually restore normal compass operation. If the compass display remains blank while the CAL label is illuminated, then the roof panel requires demagnetizing. To demagnetize, use Special Tool 6029 for demagnetizing the roof panel. The procedure will demagnetize the roof and the mounting screws for the EMTM. It is important that you follow the instructions below exactly. The mounting screws and the mounting bracket around the compass area are steel, and therefore aid in the demagnetizing of the roof panel.
1. Be sure the ignition switch is in the OFF position before you begin the procedure.
2. Plug the demagnetizing tool into a standard 110/115 volt AC outlet, keeping it at least 12 inches away from the compass area when plugging it in.
3. Slowly approach and contact the EMTM mounting screw with the plastic coated tip of the tool for at least two seconds.
4. With the tool still energized, slowly back it away from the screw until the tip is at least 12 inches from the screw head.
5. Repeat the first step with all the EMTM mounting screws.
6. After you have pulled away at least 12 inches from the mounting screw, remove the demagnetizing tool from inside the vehicle and disconnect it from the electrical outlet.
7. Place an 8 1/2 x 11 inch piece of paper length wise on the roof of the vehicle directly above the compass. The purpose of the paper is to protect the roof panel from scratches and to define the area to be demagnetized.
8. Plug in the tool, keeping it at least two feet away from the compass unit.
9. Slowly approach the center of the roof panel at the windshield with the tool.
10. Contact the roof panel with the tip of the tool. Using slow sweeping motions of 1/2 inch between sweeps, move the tool front to back approximately four inches either side of the center line and at least 11 inches back from the windshield.
11. With the demagnetizing tool still energized, slowly back away from the roof panel until the tip is at least two feet from the roof before unplugging the tool
12. Recalibrate the compass (refer to the compass calibration procedure).