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HomeTips & GuidesHow to Wire a Torque Converter Lockup Switch – A Detailed Guide

How to Wire a Torque Converter Lockup Switch – A Detailed Guide

As a car geek, I am sure you are here to know how to wire a torque torque converter lockup switch. This device helps you save on fuel and reduces heat build-up while helping your car achieve performance in various driving conditions. 

Whether you’re a DIYer or a professional, follow along as I show you how to wire a torque converter lockup switch.

What Is a Lockup Torque Converter?

Before we can talk about the lockup torque converter, let’s first know what a torque converter is. Now, assume you have a primary source of rotation power, like the engine. 

For your car to move, this rotational power has to move from the engine to the crankshaft and finally to the wheels. 

Therefore, a torque converter is the device that is responsible for this mechanism. In short, a torque converter refers to a coupling that connects and transfers power from the engine to the transmission. 

Apart from transferring rotational power, the device multiplies the rotational power when your engine output is low. It also creates more torque for a sudden stoppage, acting like brakes. 

Lockup torque convert definition.

While modern torque converters enhance motor torque by about 3 times, earlier versions brought about RPM slippage. 

The problem with this slippage is the heating created due to the transmission of oil turbulence. When manufacturers discovered this, they began utilizing vanes to cool the oil. 

Although this worked in small cars it still wasted energy and fuel and became inefficient in large machines. Automakers then developed the lockup torque converter to curb the above vices. 

Therefore, a torque converter with a clutch to help smooth power transmission. 

When your car engages this lock, your transmission and the engine lock at a 1:1 drive ratio, resulting in power efficiency. 

In other words, it’s a unique switch that tells your engine and the transmission to spin independently for a smooth start. 

It also determines when they should lock tightly and spin at the same speed for enhanced fuel economy.

Cars’ torque converters

Cars’ torque converters

How Does a Lockup Torque Converter Work?

As we have established above, the primary function of the lockup torque converter is to eliminate energy loss. 

The device comes in modern automatic transmission cars and is located between the engine flexplate and the automatic transmission. 

To understand how it works, you should first know that it uses fluid to transmit the rotational power. 

When you step on your gas pedal, the engine transfers its power through the fluid to the torque converter. 

From there, the liquid creates pressure that rotates the turbine in the converter. Once you attain high speeds (65 kph) and other conditions, such as steady cruising, you activate the lockup mechanism.

 In this scenario, a smart clutch directly connects the engine output to the transmission shaft input. 

This direct connection hooks the impeller and the turbine, reducing slippage and making the transmission more efficient. 

Therefore, you can expect 100% power to the torque converter, which reduces heat and increases fuel efficiency.

How to Wire a Torque Converter Lockup Switch

As we said earlier, you need to wire this switch properly not only for fuel economy but also longevity of your transmission.

 However, before you begin, you need an appropriate lockup torque converter lockup switch kit.

 It includes the necessary harness, connectors, and a switch. You will also need a wire cutter or striper, multimeter, and insulating tape or heat shrink tubbings. Once you collect the above items, follow the steps below:

  • First, check your vehicle manual to locate the transmission connector. It may be in the cabin or near the transmission itself, depending on your car model.
  • From there, find your vehicle wires that connect the torque converter lockup solenoid, usually near the transmission. You may also use your vehicle wiring diagram to make it easier. Then, mount the switch in an easily accessible location like the dashboard. 
  • After that, cut the wire connecting the solenoid and ensure you have enough length for your work.
  • Strip the insulator at the end of the wire to the solenoid and the lockup switch harness to facilitate connection.
  • Now connect the two wires of the switch harness to their respective ends at the lockup solenoid.
  • Once through, you can use the insulating tape or heat shrink tubing to secure the joints to prevent short circuits.
  • You may now drive your car and test the connection at different speeds. Ensure you engage the switch to activate the lockup torque converter and see how your vehicle responds. 
Torque converter repair

Torque converter repair

Lockup Torque Converter Failures

Like any other part of your car, your lockup converter may fail in various ways. For example, it can remain locked, which in turn can cause your engine to stall when you brake your car.

 It can also fail to local when you hit its engagement conditions. In such a case, your car consumes much fuel, and the radiator heats up, thus reducing its life span. Lastly, you may see your lockup mechanism slip when you engage it, increasing your engine speed constantly. 

However, you may note that your lockup mechanism may not engage unless your coolant temperature hits 120 degrees Fahrenheit. 

Also, when using a lockup overdrive unit, you may see a hindrance to the lockup torque converter. 

All in all, it is easy to tell when your lockup converter fails to work. For instance, you can check transmission shaft timing and quality or use an external tachometer.

 In addition, you can also spot the lockup torque converter unlocking when you engage the brakes or release the throttle.

 A torque converter

 A torque converter


With the research above, I trust you can now wire your torque converter lockup switch and save fuel usage.

I am Lillian Yang, having been a sales manager for over 10 years.

I have received many positive reviews from customers. They have praised our excellent service, on-time delivery, and high-quality cable assemblies.

For your projects, please provide cable assembly files/images/smples, etc., so that I can send you a quotation within 24 hours.

Contact me now and let’s get started on building your wire harnesses!

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