Mirror Compass Display Inoperative or Inaccurate

Mirror Compass Display Inoperative or Inaccurate

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

The inside rearview mirror (ISRVM) uses 2 magnetic field sensors for compass direction. One sensor is for north and south, the other is for east and west. The ISRVM supplies a signal and low reference to each sensor. As the vehicle travels with or against the earths magnetic pull, there will be a change in voltage on one or both sensors. As a result of the change in voltage, the ISRVM changes the heading on the compass display. The internal fault detection for the compass is handled by the ISRVM.

Circuit/System Testing

1. Ignition ON, compass ON, verify that there is a compass reading on the display.

^ If the display is blank, replace the ISRVM.
^ If the display shows the letter C or CAL, perform the compass calibration procedure. Refer to Compass Calibration and Magnetic Variance.

2. Verify that the compass reading on the display is correct.

^ If not correct, perform the compass magnetic variation adjustment procedure. Refer to Compass Calibration and Magnetic Variance.

3. If the display is still incorrect, replace the ISRVM.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests