Mirror Compass Display Inoperative or Inaccurate

Mirror Compass Display Inoperative or Inaccurate

Diagnostic Instructions

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


Reference Information
Schematic Reference

* Instrument Cluster Schematics (Instrument Cluster Schematics)
* Inside Rearview Mirror Schematics (Inside Rearview Mirror Schematics)

Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Automatic Day-Night Mirror Description and Operation (Automatic Day-Night Mirror Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)


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 (Description and Operation) .

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 (Description and Operation) .

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



Repair Instructions

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


Control Module References (Programming and Relearning) for ISRVM replacement, setup, and programming