1991 Chevy S10 Ignition Wiring Diagram

The ignition wiring diagram is an essential tool for any mechanic or car enthusiast looking to diagnose or repair electrical issues in their 1991 Chevy S10. This guide will provide a detailed breakdown of the wiring diagram and offer tips and tricks for troubleshooting common problems.

Understanding the Wiring Diagram

The first step in diagnosing any electrical issue is to understand the wiring diagram. The 1991 Chevy S10 ignition wiring diagram is divided into several sections, each representing a different component or system of the vehicle. These sections include:

Section Description
Battery Power source for the vehicle’s electrical system
Starter Responsible for turning the engine over
Ignition Switch Controls the power to the ignition system
Ignition Coil Converts the battery’s low voltage to high voltage needed for ignition
Distributor Distributes the high voltage to each spark plug
Spark Plugs Creates spark to ignite the fuel in the engine

It is important to study each section of the wiring diagram to understand how they all work together to start the vehicle. Keep in mind that the ignition system is just one part of the overall electrical system, and any issues with other components can affect the ignition system.

Interpreting the Wiring Diagram

The wiring diagram is a visual representation of the electrical connections in your vehicle. Each wire is color-coded and labeled to help identify its purpose. A typical wire code may look like “BLK/YEL” or “RED/BLK,” with the first color indicating the primary color and the second color indicating the stripe color.

Each wire is also labeled with a number, which corresponds to the wiring diagram key. The key lists each wire and its purpose. For example, wire “E2” may be labeled as “Ignition Switch Input” and wire “B+” may be labeled as “Battery Positive.”

Common Wiring Diagram Symbols

In addition to color-coded wires and labels, there are also several symbols used throughout the wiring diagram to represent specific components or actions. Some common symbols include:

Symbol Description
Battery Represents the battery power source
Ground Represents a grounding point in the electrical system
Solenoid Represents a solenoid component in the electrical system
Switch Represents an electrical switch

Common Issues and Troubleshooting Tips

Despite the complexity of the ignition system, there are several common issues that can be easily diagnosed and fixed. Below are some of the most common issues and their corresponding solutions:

Issue #1: No Start

If the vehicle won’t start, there may be an issue with the battery, starter, or ignition system. Here are some steps to diagnose and fix the issue:

  1. Check the battery voltage. It should read at least 12 volts. If it is low, charge the battery or replace it.
  2. Check the starter relay. This can be done by turning the key to the “start” position and listening for a clicking sound. If you hear a clicking sound, the relay is likely working. If you don’t hear anything, the relay may need to be replaced.
  3. Check the ignition switch. If the switch is faulty, it may not be sending power to the starter. Check for continuity between the ignition switch and starter solenoid wires.

Issue #2: Misfiring Engine

If the engine is misfiring, it could be due to a problem with the ignition system. Here are some steps to diagnose and fix the issue:

  1. Check the spark plugs. Make sure they are clean and properly gapped.
  2. Check the spark plug wires. Make sure they are properly connected and not damaged.
  3. Check the distributor cap and rotor. Make sure they are clean and not worn out.
  4. Check the ignition coil. Use a multimeter to test the resistance of the coil. If it is out of spec, replace the coil.


Q: What is the purpose of the ignition system?

The ignition system is responsible for starting the engine by creating a spark to ignite the fuel. It consists of several components, including the battery, starter, ignition switch, coil, distributor, and spark plugs.

Q: What should I do if my vehicle won’t start?

If your vehicle won’t start, first check the battery voltage and starter relay. If those are working properly, check the ignition switch and related wiring. If you are still unable to start the vehicle, it may be best to consult a mechanic.

Q: What is a multimeter and how do I use it?

A multimeter is a tool used to measure electrical values such as voltage, current, and resistance. To use it, first set the dial to the desired function (e.g. voltage), then touch the probes to the corresponding wires or components. The multimeter will display the value being measured.

Q: How often should I replace my spark plugs?

It is recommended to replace your spark plugs every 30,000 to 50,000 miles. However, if you experience any issues with misfiring or rough idling, it may be necessary to replace them sooner.