Mechanics

ODOMETER NOT WORKING

1996 Ford Mustang

Electrical problem
1996 Ford Mustang 6 cyl Two Wheel Drive Automatic 105000 miles

I have the same plague as most Fords odometer gear self-destruction, but after replacing the gears and checking twice, still no odometer. The speedometer works just fine. Any ideas?
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Danny_C
January 12, 2009.




SPEEDOMETER/ODOMETER INACCURATE
Road test vehicle. If the speedometer is operating, go to next step. If speedometer is not operating, go to step 5).
Drive vehicle over a known, measured distance. If odometer is reading accurately, go to next step. If inaccurate, go to step 4).
Drive vehicle at a steady speed over a known, measured distance and record time taken to travel that distance. If speedometer meets Speedometer Calibration Tolerance specifications, system is okay. See SPEEDOMETER CALIBRATION TOLERANCE table. If speedometer fails to meet speedometer calibration tolerance, replace speedometer assembly.
SPEEDOMETER CALIBRATION TOLERANCE (1)
Actual Speed-MPH. Allowable Range-MPH
30.27.8-34.7
60.57.7-64.5
(1)Odometer measured over actual 10 miles: 9.6-10.3 miles.

Check for correct driven gear on speed sensor. If driven or drive gear is suspect, refer to manufacturer's parts department for correct specifications in relation to final drive ratio and tire size. If parts are correct, go to next step. If parts are not correct, install correct parts and retest system. See Fig. 5.
Raise drive wheels off ground and support vehicle. Disconnect vehicle speed sensor connector. Connect and AC voltmeter between output pins of VSS. Start engine, operate drive wheels in gear and observe voltmeter. If voltage is 1.3-6.1 volts, go to step 8). If voltage is not correct, go to next step.
Disconnect VSS from automatic transmission. Verify presence of speedometer driven gear with all teeth in good condition and presence of retainer clip. If driven gear teeth are okay and clip is present, go to next step. If gear is damaged or clip missing, replace with proper speedometer gear and clip and retest system.
Verify presence of speedometer drive gear on output shaft of transmission. If drive gear is present, go to next step. If drive gear is not present, repair transmission as necessary.
Using voltmeter, verify battery voltage at output side of fuse No. 8. See Fig. 2. If voltage is present, go to next step. If voltage is not present, replace fuse and retest system.
Using voltmeter, verify battery voltage at input side of fuse No. 8. If voltage is present, go to next step. If voltage is not present, repair for open in wiring to fuse and retest system. See WIRING DIAGRAMS.
Disconnect negative battery cable and remove instrument cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Disconnect instrument cluster connectors C1 and C2. See Fig. 3 and Fig. 4. Reconnect negative battery cable and turn ignition switch to RUN position. Check for battery voltage at cluster connector C1, pin No. 4 (Light Green/Yellow wire). If battery voltage is present, go to next step. If battery voltage is not present, repair short or open in circuit No. 54 (Light Green/Yellow wire) and retest system.
Turn ignition switch to OFF position. Measure resistance between ground and cluster connector C1, pin No. 6 (Pink/Orange wire). If resistance is less than one ohm, go to next step. If resistance is more than one ohm, repair circuit as required and retest system.
Using an ohmmeter, measure resistance between ground and cluster connector C1, pin No. 5. If resistance is less than one ohm, repair circuit No. 679 (Gray/Black wire) for short circuit and retest system. If resistance is more than one ohm, go to next step.
Using an ohmmeter, connect cluster connector C1, pin No. 5 (Gray/Black wire) and circuit No. 679 (Gray/Black wire) at VSS connector. If resistance is less than one ohm, go to next step. If resistance is more than one ohm, repair circuit No. 679 (Gray/Black wire) for open and retest system.
Check resistance between ground and circuit No. 676 (Pink/Orange wire) at VSS connector. If resistance is less than one ohm, go to next step. If resistance is more than one ohm, repair circuit No. 676 (Pink/Orange wire) for open and retest system.
Turn ignition switch to OFF position. Check for continuity between cluster connector printed circuit connections and gauge. If there is continuity through instrument cluster printed circuit, replace speedometer/tachometer assembly and retest system. See SPEEDOMETER/TACHOMETER under REMOVAL & INSTALLATION. If continuity is not present, replace instrument cluster printed circuit and retest system. See PRINTED CIRCUIT under REMOVAL & INSTALLATION.
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Dave H
Jan 12, 2009.
Thanks for the quick reply. The speedometer works just fine. From 0 to 75mph no problem, havent been faster in it yet: )
The original odometer gears were broken as was the worm gear on the odometer motor, but how to test the motor to see if it is the problem?
Took the unit apart twice to see if I missed something, so far no problem found.

Thanks agian,
Danny

Tiny
Danny_C
Jan 12, 2009.

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