LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Ford >> 1993 >> Probe Base, Standard >> Repair and Diagnosis >> Electrical >> Gauges >> Instrument Panel - Analog >> Testing >> Speedometer Circuit Test
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Speedometer Circuit Test

NOTE: Improper tire size will cause error in speed indication.
  1. Ensure METER fuse is okay. Turn ignition off. Unplug 14-pin connector from interior fuse panel. Remove instrument cluster. See INSTRUMENT CLUSTER under REMOVAL & INSTALLATION. Measure resistance between Black/Yellow wire on 14-pin instrument cluster harness connector and ground. If resistance is not less than 5 ohms, reconnect fuse panel and go to next step. If resistance is less than 5 ohms, repair Black/Yellow wire between fuse panel and harness connector.
  2. Turn ignition on. Measure voltage between Black/Yellow wire on harness 14-pin connector and ground. If voltage is at least 10 volts, go to next step. If voltage is not at least 10 volts, repair Black/Yellow wire between fuse panel and harness connector.
  3. Turn ignition off. Measure resistance between instrument cluster pin 1F and "+" screw on speedometer. If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, replace instrument cluster printed circuit board.
  4. Measure resistance between Black wire on 14-pin instrument cluster harness connector and ground. If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, repair Black wire to ground.
  5. Turn ignition off. Unplug connector from speed sensor, located at transaxle. Measure resistance of Black/White and Orange/Black wires between speed sensor connector and 14-pin cluster connector. If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, repair appropriate wire.
  6. Measure resistance of Black/White and Orange/Black wires between speed sensor connector and ground. If resistance is greater than 10,000 ohms, go to next step. If resistance is not greater than 10,000 ohms, repair appropriate wire.
  7. Measure resistance between instrument cluster pin 1G and SP+ terminal on speedometer. If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, replace instrument cluster printed circuit board.
  8. Measure resistance between instrument cluster pin 1J and SP- terminal on speedometer. If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, replace instrument cluster printed circuit board.
  9. Measure resistance between instrument cluster pin 1I and SP- terminal on speedometer. If resistance is less than 5 ohms, go to next step. If resistance is not less than 5 ohms, replace instrument cluster printed circuit board.
  10. Turn ignition off. Reconnect wiring to instrument cluster and speed sensor. Backprobe Black/White and Orange/Black wires on 14-pin instrument cluster connector with AC voltmeter. Drive vehicle at speeds specified in SPEED SENSOR SPECIFICATIONS table. If voltages are as specified, replace speedometer. If voltages are not as specified, replace speed sensor.
SPEED SENSOR SPECIFICATIONS

Speed (MPH) ApproximateAC Voltage
0 0
10 2.10
20 3.40
30 4.25
40 4.80
50 5.20
60 5.50
scientia non olet · About LEMON Manuals