LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> GMC >> 1998 >> Forward Control 7.4 B >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Basic Diagnostic Procedures - 7.4L >> Basic Ignition System Checks >> Dis >> Ignition Coil Test
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Ignition Coil Test

  1. Turn ignition off. Remove engine cover. Disconnect distributor lead and wiring from ignition coil.
  2. Place DVOM on high scale. Connect DVOM as shown in step 1 of illustration. See Fig 1. If reading is not infinite, replace ignition coil.
  3. Place DVOM on low scale. Connect DVOM as shown in step 2 of illustration. See Fig 2. If reading is not 0.1 ohm, replace ignition coil.
  4. Place DVOM on high scale. Connect DVOM as shown in step 3 of illustration. See Fig 3. If reading is not 5000-25,000 ohms, replace ignition coil.
  5. Reconnect distributor lead and wiring to ignition coil. Install engine cover.
Fig 1: Testing Ignition Coil - Step 1
G98B01081Courtesy of GENERAL MOTORS CORP.
Fig 2: Testing Ignition Coil - Step 2
G98D01082Courtesy of GENERAL MOTORS CORP.
Fig 3: Testing Ignition Coil - Step 3
G98F01083Courtesy of GENERAL MOTORS CORP.
scientia non olet · About LEMON Manuals