1968 John Deere 140 Wiring Diagram

John Deere 140 is a lawn tractor that was manufactured by John Deere from 1968 until 1974. It’s a popular lawn tractor with many features that make it stand apart from other lawn tractors of the same era.

Introduction

If you own a 1968 John Deere 140, you know that it’s a classic piece of machinery that requires proper maintenance to function properly. One of the most important components of the John Deere 140 is the wiring system. Without a properly functioning wiring system, your John Deere 140 will not start or run efficiently.

The wiring system of the John Deere 140 can be quite complex, especially for those who are not familiar with electrical systems. In this article, we will provide you with a detailed wiring diagram of the 1968 John Deere 140, along with a few frequently asked questions (FAQ) to help you troubleshoot any issues that you may encounter with your wiring system.

Wiring Diagram

Component Wire Color
Battery Positive Red
Fuel Gauge Sender Yellow
Starter Solenoid White
Light Switch Green
Ignition Switch Black/Red Stripe
Regulator Orange
Ammeter White
Headlights Yellow/Black Stripe
Engine Ground Black
Accessory Power Blue/White Stripe
Brake Switch Green/White Stripe
Charging Circuit White/Red Stripe

The above wiring diagram shows the different components of the John Deere 140 and their respective wire colors. It’s important to note that this wiring diagram is specific to the 1968 model year and may differ from later models.

Battery Positive

The battery positive wire is color-coded red and is connected to the positive terminal of the battery. This wire supplies power to various components of the lawn tractor, including the starter solenoid, regulator, and ammeter.

If your John Deere 140 fails to start, check the battery connections and the condition of the battery. Also, make sure that the battery positive wire is securely connected to the positive terminal of the battery.

Fuel Gauge Sender

The fuel gauge sender wire is color-coded yellow and is connected to the fuel gauge sender. This wire sends a signal to the fuel gauge and displays the amount of fuel in the fuel tank.

If your fuel gauge is not working properly, check the connections of the fuel gauge sender wire and the condition of the fuel gauge sender. Also, make sure that the fuel tank is properly filled with fuel.

Starter Solenoid

The starter solenoid wire is color-coded white and is connected to the starter solenoid. This wire supplies power to the starter motor when the ignition switch is turned to the start position.

If your John Deere 140 fails to start, check the connections of the starter solenoid wire and the condition of the starter solenoid. Also, make sure that the battery is fully charged.

Light Switch

The light switch wire is color-coded green and is connected to the light switch. This wire supplies power to the headlights when the light switch is turned on.

If your headlights fail to turn on, check the connections of the light switch wire and the condition of the light switch. Also, make sure that the bulbs are properly installed and functioning properly.

Ignition Switch

The ignition switch wire is color-coded black/red stripe and is connected to the ignition switch. This wire supplies power to the various components of the lawn tractor, including the starter solenoid and ammeter, when the ignition switch is turned to the on position.

If your John Deere 140 fails to start or runs poorly, check the connections of the ignition switch wire and the condition of the ignition switch. Also, check the condition of the spark plug and the fuel system.

Regulator

The regulator wire is color-coded orange and is connected to the regulator. This wire regulates the charging system and ensures that the battery is properly charged.

If your battery fails to hold a charge, check the connections of the regulator wire and the condition of the regulator. Also, check the condition of the alternator and the charging system.

Ammeter

The ammeter wire is color-coded white and is connected to the ammeter. This wire displays the charging system status and indicates whether the battery is properly charged or not.

If your ammeter fails to display properly, check the connections of the ammeter wire and the condition of the ammeter. Also, check the condition of the battery and the charging system.

Headlights

The headlights wire is color-coded yellow/black stripe and is connected to the headlights. This wire supplies power to the headlights when the light switch is turned on.

If your headlights fail to turn on, check the connections of the headlights wire and the condition of the headlights. Also, make sure that the bulbs are properly installed and functioning properly.

Engine Ground

The engine ground wire is color-coded black and is connected to the engine block. This wire ensures that the engine is properly grounded and prevents electrical issues.

If your John Deere 140 experiences electrical issues, check the connections of the engine ground wire and the condition of the engine block. Also, check the condition of the other electrical components.

Accessory Power

The accessory power wire is color-coded blue/white stripe and is connected to various components of the lawn tractor, including the fuel gauge and light switch. This wire supplies power to these components when the ignition switch is turned to the on position.

If your fuel gauge or light switch fail to function properly, check the connections of the accessory power wire and the condition of the components that are powered by this wire.

Brake Switch

The brake switch wire is color-coded green/white stripe and is connected to the brake switch. This wire ensures that the lawn tractor will not start unless the brake pedal is depressed.

If your John Deere 140 starts without depressing the brake pedal, check the connections of the brake switch wire and the condition of the brake switch. Also, check the condition of the other safety features of the lawn tractor.

Charging Circuit

The charging circuit wire is color-coded white/red stripe and is connected to the alternator. This wire supplies power to the charging system and ensures that the battery is properly charged.

If your John Deere 140 fails to hold a charge, check the connections of the charging circuit wire and the condition of the alternator. Also, check the condition of the regulator and the charging system.

FAQ

1. Why won’t my John Deere 140 start?

If your John Deere 140 fails to start, check the battery connections and the condition of the battery. Also, make sure that the starter solenoid wire is securely connected to the starter solenoid and the battery positive wire is properly connected to the positive terminal of the battery. Additionally, check the ignition switch, spark plug, and fuel system.

2. Why is my fuel gauge not working?

If your fuel gauge is not working properly, check the connections of the fuel gauge sender wire and the condition of the fuel gauge sender. Also, make sure that the fuel tank is properly filled with fuel.

3. Why are my headlights not turning on?

If your headlights fail to turn on, check the connections of the headlights wire and the condition of the headlights. Also, make sure that the bulbs are properly installed and functioning properly.

4. Why is my John Deere 140 experiencing electrical issues?

If your John Deere 140 experiences electrical issues, check the connections of the engine ground wire and the condition of the engine block. Also, check the condition of the other electrical components, including the wiring harness and the battery.

5. Why won’t my John Deere 140 hold a charge?

If your John Deere 140 fails to hold a charge, check the connections of the charging circuit wire and the condition of the alternator. Also, check the condition of the regulator and the charging system.

Conclusion

The wiring system of the 1968 John Deere 140 can be complex, but with the proper wiring diagram and knowledge of the components, you can troubleshoot any issues that you may encounter. Always ensure that the connections are secure and the components are functioning properly to maintain the proper functioning of your John Deere 140.