When it comes to restoring vintage Chevy trucks, one of the key components to get right is the ignition system. The ignition switch wiring diagram for a 1972 Chevy truck can be hard to find, but it’s essential information for anyone looking to restore one of these classic vehicles. In this article, we’ll break down the wiring diagram and explain what each wire does, so you can get your truck back on the road.
What is an Ignition System?
Before we dive into the wiring diagram, let’s take a quick overview of what an ignition system does. The ignition system is what starts and stops the engine. It provides the high voltage spark that ignites the fuel in the engine cylinders, which gets the pistons moving and starts the engine running. The key component in this system is the ignition switch, which has to be wired up correctly to function properly.
The ignition switch is the electrical component that sends a signal to the starter motor, which engages the engine crankshaft. In order for the ignition switch to work correctly, it has to be wired up correctly. Let’s take a look at the wiring diagram for a 1972 Chevy truck ignition switch.
The Wiring Diagram
The ignition switch wiring diagram for a 1972 Chevy truck consists of 10 wires that are connected to the switch. These wires are color-coded and serve different functions. Let’s break them down:
| Wire | Color | Function |
|---|---|---|
| 1 | Yellow | Battery |
| 2 | White | Accessory |
| 3 | Purple | Starter solenoid |
| 4 | Orange | Ignition coil |
| 5 | Black | Ground |
| 6 | Green | Accessory |
| 7 | Brown | Ignition signal |
| 8 | Red | Battery |
| 9 | Dark blue | Ignition switch to starter solenoid |
| 10 | Tan | Ignition switch to neutral safety switch |
Yellow Wire – Battery
The yellow wire is connected to the positive terminal of the battery. It provides power to the ignition switch and other electrical components in the truck.
The yellow wire should always have power, even when the ignition switch is in the off position. This ensures that the truck’s electrical system is always operational, and that the battery is charging when the truck is running.
If the yellow wire doesn’t have power, there may be a problem with the battery or the wiring connecting it to the ignition switch.
White Wire – Accessory
The white wire is connected to the accessory terminal of the ignition switch. It provides power to the truck’s accessory systems, such as the radio, lights, and windshield wipers.
The white wire should only have power when the ignition switch is in the accessory or on position. This prevents the accessory systems from draining the battery when the truck is turned off.
If the white wire doesn’t have power when the ignition switch is in the appropriate position, there may be a problem with the ignition switch or the wiring connecting it to the accessory systems.
Purple Wire – Starter Solenoid
The purple wire is connected to the starter solenoid on the engine. It sends a signal to engage the starter motor and crank the engine.
The purple wire should only have power when the ignition switch is turned to the start position. If the wire has power when the ignition switch is off, there may be a short circuit in the wiring or a problem with the solenoid.
Orange Wire – Ignition Coil
The orange wire is connected to the ignition coil, which provides the high voltage spark to the engine’s spark plugs. It’s responsible for starting and running the engine.
The orange wire should only have power when the ignition switch is in the on or start position. This ensures that the engine’s ignition system is only active when the engine is running.
If the orange wire doesn’t have power when the ignition switch is in the appropriate position, there may be a problem with the ignition switch or the wiring connecting it to the ignition coil.
Black Wire – Ground
The black wire is connected to the truck’s ground system. It provides a path for electrical current to flow back to the battery.
The black wire should always have continuity to the truck’s frame or chassis. If it doesn’t, there may be a problem with the wiring or the ground connection.
FAQ
What happens if the ignition switch wiring is incorrect?
If the ignition switch wiring is incorrect, the truck may not start or run properly. It could cause damage to the engine, electrical system, or other components.
What should I do if I suspect a problem with the ignition switch wiring?
If you suspect a problem with the ignition switch wiring, you should have it inspected by a qualified mechanic. They can diagnose the issue and recommend the appropriate repairs.
What other components are important in the ignition system?
In addition to the ignition switch, other important components in the ignition system include the distributor, spark plugs, and ignition module or control unit. These all work together to provide the high voltage spark that starts and runs the engine.
Can I replace the ignition switch myself?
Replacing the ignition switch can be a complex and involved process. It’s recommended that you have it done by a qualified mechanic to ensure that it’s done correctly and safely.
How can I ensure that my truck’s ignition system is in good condition?
The best way to ensure that your truck’s ignition system is in good condition is to have it inspected regularly by a qualified mechanic. They can check for wear, damage, and other issues that could affect its performance.
What should I do if my truck’s ignition system fails?
If your truck’s ignition system fails, you should have it inspected by a qualified mechanic. They can diagnose the issue and recommend the appropriate repairs. In some cases, the ignition system may need to be completely replaced.
Hopefully, this article has given you a better understanding of the ignition switch wiring diagram for a 1972 Chevy truck. If you have any questions or concerns, be sure to consult a qualified mechanic before attempting any repairs or modifications to your truck’s electrical system.
