What Tools Do I Need To Test The Ignition System?

Although the tests in this article easy and simple, you do need some specific tools to perform them with. Here's the list:

  1. An HEI Spark Tester
    1. This inexpensive spark tester is a MUST have tool to be able to correctly diagnose the Coil-On-Plug ignition coils on your GM vehicle with the info and tests in this article (don't have an HEI spark tester? Need to buy one? You can buy it here: OTC 6589 Electronic Ignition Spark Tester).
    Don't use a regular spark plug instead of a spark tester.
  2. Battery jump start cables.
  3. A digital multimeter or analog multimeter.
  4. A helper.
    1. You'll need someone to help you crank the engine while you perform the tests in the engine compartment.
  5. A repair manual.
    1. For whatever remove and replace info you'll need that is not covered by this article.

Ignition Module Circuit Descriptions

Ignition Module Circuit Descriptions. How To Test A Misfire / No Spark-No Start Condition (4.3L, 5.0L, 5.7L 96-04)

The ignition control module (ICM) on your GM car (pick up, van, mini-van, or SUV) has 4 wires (circuits) coming out of it. Below are the descriptions of what each circuit does. Each circuit is identified by a letter, and this is the same letter that you will find on the ignition module's connector.

  1. Circuit labeled A -Pink (PNK) Wire:
    1. Power (12 V) Circuit.
  2. Circuit labeled B -White (WHT) Wire:
    1. Ignition Control (IC) Signal. This signal is provided courtesy of the Powertrain Control Module (PCM) and I usually refer to it as the Triggering Signal.
  3. Circuit labeled C -Black With White Stripe (BLK/WHT) Wire:
    1. Engine Ground Circuit.
  4. Circuit labeled D -White With Black Stripe (WHT/BLK) Wire:
    1. Switching Signal Circuit.

The following ignition system circuit diagram may be of help: Ignition System Circuit Diagram (1996-1999 Chevy/GMC Pick Up And SUV).

Ignition Coil Circuit Descriptions

Ignition Coil Circuit Descriptions. How To Test A Misfire / No Spark-No Start Condition (4.3L, 5.0L, 5.7L 96-04)

The ignition coil on your car or truck may have or may not have 3 wires coming out of it (if your vehicle has a tachometer, the ignition coil's connector will have 3 wires, if does not, then it'll have 2 wires).

Whether it does or doesn't doesn't matter, the info in this test article still applies. Below are the descriptions of what each circuit does. Each circuit is identified by a letter, and this is the same letter that you will find on the ignition coil's connector.

  1. Circuit labeled A -Pink (PNK) Wire:
    1. Power (12 V) Circuit.
  2. Circuit labeled B -White (WHT) Wire:
    1. Tach Signal for the Tachometer in the instrument cluster if equipped.
  3. Circuit labeled C -White With Black Stripe (BLK/WHT) Wire:
    1. Switching Signal Circuit. This signal is provided courtesy of the ignition control module (ICM).

The following ignition system circuit diagram may be of help: Ignition System Circuit Diagram (1996-1999 Chevy/GMC Pick Up And SUV).

Chevrolet Vehicles:
  • Astro
    • 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
  • Blazer
    • 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
  • Blazer TrailBlazer
    • 1999, 2000, 2001
Chevrolet Vehicles:
  • C1500, C2500, C3500 Pick Up
    • 1996, 1997, 1998, 1999, 2000
  • Express Van 1500, 2500, 3500
    • 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
  • G30 Van
    • 1996
  • K1500, K2500, K3500 Pick Up
    • 1996, 1997, 1998, 1999, 2000
Chevrolet Vehicles:
  • K1500, K2500 Suburban
    • 1996, 1997, 1998, 1999
  • P30 Van
    • 1996, 1997, 1998, 1999
  • S10 Blazer
    • 1994
  • S10 Pick Up
    • 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
Chevrolet Vehicles:
  • Silverado 1500 Pick Up
    • 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2007
  • Tahoe
    • 1996, 1997, 1998, 1999, 2000
GMC Vehicles:
  • Sierra C1500, C2500, C3500
    • 1996, 1997, 1998, 1999, 2000
GMC Vehicles:
  • Suburban C1500, C2500
    • 1996, 1997, 1998, 1999
  • G3500 Van & Vandura
    • 1996
  • Jimmy & Envoy
    • 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
  • K1500, K2500, K3500 Sierra
    • 1996, 1997, 1998, 1999, 2000
GMC Vehicles:
  • P3500 Van
    • 1996, 1997, 1998, 1999
  • S15 Jimmy
    • 1994
  • Safari
    • 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005
GMC Vehicles:
  • Savana Van 1500, 2500, 3500
    • 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007
  • Sonoma
    • 1994, 1995, 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004
GMC Vehicles:
  • Yukon
    • 1996, 1997, 1998, 1999, 2000, 2001, 2002
Isuzu Vehicles:
  • Hombre
    • 1997, 1998, 1999, 2000
Oldsmobile Vehicles:
  • Bravada
    • 1996, 1997, 1998, 1999, 2000, 2001
Cadillac Vehicles:
  • Escalade
    • 1999, 2000