For 1990-2009 cars

## Compass Malfunction Mirror

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | 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 sensor is for east and west. 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

Inside Rearview Mirror Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Driver Information Center (DIC) Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

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

Control Module References for ISRVM replacement, setup and programming