4L60E Transmission External Wiring Harness Diagram – What Is It?

The 4l60e is one of General Motors’ high-performance, durable, and versatile 4-speed transmissions. However, its external wiring harness is prone to damage due to defective soldering and the wires overheating. Therefore, understanding the external wiring harness diagram for the 4l60e is critical.

But what is this diagram all about? Well, the diagram illustrates the link between the different electrical components. Thus, it shows you where to find the vehicle speed sensor, brake shift, and line pressure sensor, which are electronically controlled.

So, why study this wiring harness diagram for the 4l60e? Stay here to learn this and everything else about the 4l60e external wiring harness.

External Wiring Harness Diagram For 4l60e Transmission Table

The table below will quickly look at what to expect from the external 4l60e transmission wiring harness diagram.

Components Of The External Wiring Harness Function
Upshift and downshift solenoids Controls up and downshift of transmission fluid
Vehicle speed sensor (VSS) Control the vehicle’s speed
Case ground Encloses the electrical components at ground
Main relay Electronically opens and closes the harness’ circuits
Line pressure sensor Regulates pressure
Brake switch Keeps the gear shifter in place until when you apply the brakes

What Is The 4l60e Transmission External Wiring Harness Diagram?

Essentially, it is a drawing showcasing the link between all external electrical elements of the 4l60e transmission. On the other hand, the 4l60e is an automatic transmission available in vehicles manufactured by General Motors between 1993 and 2013.

Typically, the 4 stands for 4-speed, L means the longitudinally mounted transmission, and 60 is the strength rating. Meanwhile, the E means the transmission is electronically controlled. Below is the diagram for the 4l60e transmission external wiring harness.

Image Courtesy: CPT 4L60E

From the diagram above, you can see the external wiring harness for the 4160e transmission comprises various parts. These include:

1. Shift solenoids

The external wiring harness of the 4l60e boasts two shift solenoids, including upshift and downshift. These shifts regulate the up and downshift of transmission fluid as it passes through them.

2. Case ground

The case ground covers all outer cases of the 4l60e transmission electrical components, which should be at the ground. Generally, this case is constructed from insulating materials for enhanced durable performance. 

3. Vehicle Speed Sensor (VSS)

The VSS wire helps determine the vehicle’s speed and sends the information to several pulses. You can find the sensor at the tail shaft housing on the passenger side.

4. Brake switch

This switch is built to prevent the gear shifter from moving out of place until you have pressed the brakes. In other words, the switch stays closed or electrically connected until you apply your brakes.

5. Main relay

The main relay is one of the most critical wiring harness aspects in the 4l60e transmission. Its job is to open and close the wiring harness circuits electronically.

6. Line pressure sensor

As the name suggests, this component helps regulate pressure in the 4l60e transmission control module (TCM). The sensor creates a signal based on transmission line pressure. However, it is optional to install this component.

Why Study The External Wiring Harness Diagram Of The 4l60e?

Although the 4l60e transmission is one of the most reliable by General Motors, it is still prone to several problems. These include:

  • Loss of the third gear
  • Difficulty shifting into second gear
  • Slipping problems
  • Being stuck in neutral or erratic shifting.
  • Failure to downshift or go into reverse

Nevertheless, the good news is if you understand the external wiring harness diagram of the 4l60e transmission, you can quickly diagnose most of the problems. And after diagnosing, it becomes easier to fix the issues.

The diagram also makes 4l60e transmission external wiring harness removal and installation effortless during the repair. Additionally, when you understand the diagram, testing the wiring harness and all other electrical components for resistance becomes easy.

In addition, the diagram makes finding the correct wiring harness for your transmission much more straightforward. This is important because the harness for the 4l60e transmission is different every year. It did undergo several design changes over the years.

How Many Connectors Does The 4l60E External Wiring Harness Have?

There is one ECU connector in the 4l60e transmission wiring harness for the vehicle speed. The connector for the input shaft speed is in the internal wiring harness. 

However, the connector for the vehicle speed varies in terms of the number of pins. You may come across one with 12, 16, 20, or 21 pins. But overall, the most common one is the 13-pin connector with 13 wires.

Unfortunately, you cannot use the 13-pin connector if your wiring harness has a 16-pin. So, when replacing the external wiring harness of your vehicle’s 4l60e, you must consider the number of pin connectors.

Will The 4l60e Transmission Wiring Harness Work Without A Computer?

No. The 4l60e transmission is fully electronic hence the letter E. This means you can only control it with a computer. The computer controls everything, including the line pressure sensor, brake switch, shift solenoids, gear changes, and vehicle speed sensor.

Is The 4l60e External Wiring Harness Diagram Same As The Internal?

No. Unlike the external wiring harness, which boasts a vehicle speed sensor, the internal harness features an input speed sensor. Also, the internal wiring harness diagram does not have a brake switch and line pressure sensor. Instead, it boasts a temperature sensor and pressure switch manifold.

Another difference between the two diagrams is the number of solenoids. The internal wiring harness has a TCC lockup solenoid, pressure control solenoid, and control solenoid. Therefore, you will find more wire solenoids in the interior than in the external wiring harness diagram.

Conclusion

The 4l60e transmission external wiring harness diagram is less complex-looking than its internal counterpart. So, anyone can understand it. This makes it easy to remove, install, and even replace the wiring harness when damaged. However, unlike other harnesses, this one for the 4l60e transmission cannot work without a computer.

You Can Also Read:

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *