LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Mercury >> 1982 >> LN7 Automatic Trans >> Repair and Diagnosis >> Engine Performance >> Ignition System >> Distributors & Ignition Systems - MOTORCRAFT TFI Ignition System >> Testing >> Wiring Harness Check
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Wiring Harness Check

  1. Disconnect ignition module connector from ignition module. Disconnect wire at "S" terminal of starter relay. Attach negative lead of voltmeter to distributor base and measure battery voltage at battery. With negative lead of voltmeter still connected to distributor base, check voltage in each of the following situations:
    • Positive voltmeter lead connected to terminal No. 1 of ignition module connector with ignition switch in the "RUN" position. See Fig 1.
    • Positive voltmeter lead connected to terminal No. 2 of ignition module connector with ignition switch in the "RUN" position. See Fig 1.
    • Positive voltmeter lead connected to terminal No. 3 of ignition module connector with ignition switch in the "START" position. See Fig 1.
      Fig 1: Test Points for Wiring Harness Check
      G09316170Courtesy of FORD MOTOR CO.
  2. If reading was at least 90 percent of battery voltage, proceed to "PICK-UP COIL AND IGNITION MODULE CHECK ". If reading was less than 90 percent of battery voltage, inspect for wiring harness problems or a worn or damaged ignition switch.