1987 Ford Ranger Ignition Wiring Diagram: A Comprehensive Guide

If you’re in need of a reliable ignition wiring diagram for your 1987 Ford Ranger, you’ve come to the right place. In this article, we’ll provide you with an in-depth guide on how to understand and interpret a wiring diagram. You’ll also learn how to troubleshoot and make repairs to your ignition system.

Understanding Wiring Diagrams

Before we dive into the specifics of the diagram, let’s first understand what a wiring diagram is and how to read it. A wiring diagram is a visual representation of the electrical system in a vehicle. It shows how the components are connected and where the wires run.

On the diagram, you’ll see lines that represent the wires, symbols that represent the components, and some numbers that indicate wire gauge and color. Reading a wiring diagram can be confusing at first, but with a little practice, you’ll be able to interpret it in no time.

Here are a few tips to help you read a wiring diagram:

  • Start by looking for the power source – this is usually the battery.
  • Follow the lines to see how the power is distributed to the different components.
  • Look for symbols that represent the components – these can vary depending on the diagram, but there are some standard ones that you’ll see in most diagrams.
  • Refer to the legend or key to understand what each symbol represents.

Standard Wiring Diagram Symbols

Here are some of the symbols that you might see on a wiring diagram:

Symbol Component
Battery Power source
Switch A device that opens or closes a circuit
Resistor A device that limits current flow
Lightbulb A device that converts electrical energy into light
Ground Used for connecting metal parts to the ground

The 1987 Ford Ranger Ignition Wiring Diagram

The 1987 Ford Ranger uses a fairly simple ignition system. There is a coil that is powered by the battery, and the distributor sends the spark to the correct cylinder. Here’s a breakdown of the wiring diagram:

Power Distribution

The battery supplies power to the ignition switch, which then sends power to the coil. There is also a fusible link that protects the system from overload.

Coil Wiring

The coil has four wires connected to it. The positive wire comes from the ignition switch and supplies power to the coil. The negative wire goes to the distributor and is used to trigger the spark. There are also two smaller wires that are used for the tachometer and the engine control module.

Distributor Wiring

The distributor has two wires – one for power and one for the spark signal. The power wire comes from the ignition switch, and the signal wire goes to the negative terminal of the coil.

Troubleshooting the Ignition System

If you’re having trouble with your ignition system, there are a few things you can check before you start replacing parts. Here are some common problems and how to diagnose them:

No Spark

If you’re not getting any spark, there are a few things you can check:

  • Make sure the battery is fully charged and the connections are clean and tight.
  • Check the fusible link to make sure it’s not blown.
  • Check the wires to the coil and distributor to make sure they’re not damaged or disconnected.
  • Check the distributor cap and rotor for wear or damage.

Weak Spark

If you’re getting a weak spark, there are a few things you can check:

  • Check the spark plug wires to make sure they’re not damaged or worn.
  • Check the spark plugs for wear or fouling.
  • Check the coil for resistance – it should be between 6,000 and 15,000 ohms.
  • Check the distributor cap and rotor for wear or damage.


What does the fusible link do?

The fusible link is designed to protect the wiring and components from overload. If there is a short circuit or excessive current flow, the link will melt and open the circuit.

What is the resistance range for the coil?

The resistance of the coil should be between 6,000 and 15,000 ohms.

How often should I replace the spark plugs?

Spark plugs should be replaced every 30,000 miles or as recommended by the manufacturer.

What is a distributor cap and rotor?

The distributor cap and rotor are part of the distributor assembly. The cap covers the contacts that send the spark to the correct cylinder, and the rotor spins and makes contact with the cap contacts.

What is a tachometer?

A tachometer is a gauge that measures engine speed in revolutions per minute (RPM). It’s useful for monitoring engine performance and diagnosing problems.

By understanding the wiring diagram and following the troubleshooting tips, you should be able to diagnose and repair most problems with your 1987 Ford Ranger ignition system. Remember to always use caution when working with electrical components and to follow the manufacturer’s instructions. Good luck!