It’s a common scenario – you’re checking out a car engine and you see a three wire coolant temperature sensor wiring diagram. Most of us just don’t understand the basics of how a coolant temperature sensor works, let alone how to wire it up. But with a little knowledge, you can make sense of the wiring diagram and even repair or replace the sensor yourself.
Understanding the Basics
A 3 wire coolant temperature sensor wiring diagram is based on the fact that a coolant temperature sensor is a variable resistor. In its most basic form, the coolant temperature sensor has three wires – one that is connected to the battery positive terminal, one that is connected to the ground wire and one that is connected to the engine block or cylinder head. The resistance of the coolant temperature sensor varies as the temperature of the engine coolant changes. When the resistance is high, the temperature is low, and when the resistance is low, the temperature is high.
Making Connections
The three wires are generally labeled on the wiring diagram as “hot”, “ground”, and “signal”. The hot wire is connected to the battery positive terminal and delivers power to the coolant temperature sensor. The ground wire is connected to the battery negative terminal and provides the return path for the current. The signal wire is connected to the engine block or cylinder head and provides the voltage signal to the engine computer for temperature readings.
Conclusion
Having a basic understanding of a 3 wire coolant temperature sensor wiring diagram can help you diagnose and repair a faulty coolant temperature sensor. With a few simple tools, you can easily troubleshoot the coolant temperature sensor and replace it if necessary. Whether you’re working on a car engine, a motorcycle, or a lawnmower, understanding the basics of how the coolant temperature sensor works can save you a lot of headaches in the long run.
