General Information

The electronic compass is available as part of the instrument cluster assembly. The electronic compass system is factory installed and consists of the following:
1. Compass display within the instrument cluster
2. Electronic compass module

The compass display is located in the instrument cluster, to the left of the gauges. The compass display indicates the vehicle heading, relative to the Earth's magnetic fields in a directional display relative to symbolic horizon lines and road lines. In addition, word and symbol displays are provided for use in calibrating the compass and for diagnosing malfunctions which might occur.

The electronic compass module includes a fluxgate magnetic field sensor and a microprocessor. The microprocessor receives inputs from the sensor and provides outputs to the compass display within the instrument cluster. This compass operates on the same principle as other fluxgate compasses. The sensor measures the direction of the Earth's magnetic field by measuring its strength in two perpendicular coils, these coils are part of the fluxgate sensor. The fluxgate sensor converts the magnetic field strength into electrical signals that the cluster can understand.

The vehicle heading is sent to the compass display via CKT 336 (PPL/WHT). The electronic compass module sends the vehicle heading only when requested by the compass display. When the compass display receives the heading information, the information is converted into a display format which is shown on the compass display.

The clock input CKT 337 (TAN/WHT) is a timing signal that keeps the electronic compass module and the compass display communicating at the right time and rate. The clock signal must be functioning for data to be exchanged between the module and display.

The compass display receives Vehicle Speed Sensor (VSS) input via CKT 817 (DK GRN).

The earth's magnetic field is not always the same direction as geographical north. Refer to Variation Mode. Variation Mode

There is no periodic service or maintenance required on the compass system. Once the compass has been properly calibrated it should not require adjustment other than updating the zone number if the vehicle is driven to a new zone.

The Earth's magnetic field is weak compared to most magnets (i.e. a radio speaker magnet is thousands of times stronger than the Earth's magnetic field), this means that the electronic compass module must he sensitive. For this reason, many things can affect the modules ability to measure the Earth's field accurately. The following commonly found factors can affect compass accuracy:
1. Magnetic character of vehicle
2. Rear Defogger system
3. Hills and road crowns
4. Bridges, tunnels and tall buildings
5. Naturally occurring disturbances