Electronic Compass; Diagnosis And Testing; Principles Of Operation; Inspection And Verification - Ford ST3093-A Instructions Manual

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DIAGNOSIS AND TESTING

Electronic Compass

Special Tool(s)

Principles of Operation

NOTE:
The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).
NOTE:
This procedure is only applicable to vehicles without navigation. For vehicles with navigation, refer to Section 415-00.
The compass display (located in the Front Display Interface Module (FDIM)) receives battery voltage from the SJB. The compass module (integral to the
auto-dimming interior mirror) provides hardwired vehicle directional inputs to the Instrument Panel Cluster (IPC), which sends the compass information to
the FDIM over the Medium Speed Controller Area Network (MS-CAN). The compass is capable of self-calibrating. This decreases the need to manually set
the compass. If the compass is displaying a heading (and not displaying the C or CAL indicator), the compass is in auto-calibration mode. In this mode, the
compass automatically calibrates for changes in vehicle magnetics over the life of the vehicle. This auto-calibration mode makes sure the compass heading is
always accurate. If the compass displays the C or CAL indicator for an extended period of time (longer than 5 seconds), this indicates the compass has been
placed in the manual calibration mode and therefore, requires manual calibration.

Inspection and Verification

1. Verify the customer concern.
2. Visually inspect for obvious signs of mechanical or electrical damage.
Visual Inspection Chart
Mechanical
• Compass module (integral to the auto-dimming interior mirror)
• Front Display Interface Module (FDIM)
3. If an obvious cause for an observed or reported concern is found, correct the cause (if possible) before proceeding to the next step.
4. NOTE:
Make sure to use the latest scan tool software release.
If the cause is not visually evident, connect the scan tool to the Data Link Connector (DLC).
Electronic Compass
Fluke 77-IV Digital Multimeter
FLU77-4 or equivalent
Vehicle Communication Module (VCM) and Integrated Diagnostic System (IDS) software
with appropriate hardware, or equivalent scan tool
Flex Probe Kit
105-R025D or equivalent
• Smart Junction Box (SJB) fuse(s):
— 14 (10A) (FDIM)
— 41 (15A) (compass module)
• Wiring, terminals or connectors
2011 Mustang, 2/2011
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Electrical