Short Circuit in a Car: Causes and Solutions
A short circuit happens due to a fault in wiring that shunts electricity before it reaches its final destination. It is different from an open circuit where there is no current flow at all. In both cases, the current doesn’t reach the intended system or component – but a short circuit carries certain risks. If not fixed promptly and properly, it can drain the battery, damage electronic components and even start a fire in the car.
This guide will help you identify a short circuit in your car and fix it to prevent driving emergencies. However, it is important to first understand how the car circuit works, as it’ll help you identify where the short circuit is and how can you fix it.
An Overview of Car Circuits
The electric current in a car passes through different types of circuits. A short in any point of these circuits is capable of disturbing the flow of electricity. A car’s electrical system can be divided into two circuits namely actuator and sensor. In order to understand how a short circuit disrupts the flow, it is important to learn how both these circuits work in a car.
- Actuator: This includes light sensors, speed sensors, oxygen sensors, and switches
- Sensor: This includes lights and motors
The Sensor Circuit
A classic sensor circuit is the wiring between the Engine Coolant Temperature Sensor (ECT) and the Engine Control Module (ECM). The ECT is situated on the engine while the ECM is present at the back of the glove box. A 5V voltage goes from the ECM towards the ECT while altering resistance according to the temperature. If the ECT sensor is not hot, it means there is high resistance and less voltage reaches the ECM. Contrary to this, when the engine is ignited, the resistance in the ECT sensor drops, transmitting higher voltage to the ECM.
The Actuator Circuit
An actuator circuit of a headlight passes through the wiring that goes from the battery to relays and fuses, and ultimately to the switch and bulb of the headlight before it goes back to the battery. There is always power present in the headlight switch. However, it is not transmitted to the headlight until the driver turns on the switch.
Types of Car Short Circuits
Both the actuator and sensor circuits work properly when the wiring is intact. However, the circuit can be broken due to many reasons like chafing wires, mishandling while installation, damage by rodents, impact damage, and moisture.
There are two types of short circuits in vehicles where the current changes its path on its own and never reaches the actuator or sensor it is meant to power.
Short to Ground
It refers to a situation where the current flows from the circuit to the body of the car. Improperly insulated or chafed wires in this circuit can touch the engine or body causing a short to ground circuit. This can cause inoperative motor lights, blown fuses, or missing sensors. For instance, a chafed wire which is short to the ground can lead to a blown headlight fuse. Though it may prevent overheating of a circuit, the headlights will be off.
Short to Power
When many circuits are placed closely, short to power may happen. In this situation, there is a probability of cut or chafed wires touching each other and disturbing the flow of current. For instance, when installing a device, you may mistakenly insert a screw in the wire harness that is connecting several wires. Here, when you turn on the headlights, the current may flow towards the horn or when pushing a brake, your reverse headlights may start blinking instead.
How to Find a Short Circuit
Finding the fault and fixing it can be a difficult task for anyone who has little or no knowledge of electric circuits. We recommend calling for professional help if you suspect a short circuit in your car. If you have experience in working with electric circuits, you can follow these steps to see if you can identify the cause:
Remove the battery’s negative pole and connect your circuit test light with the negative pole. Now touch the tester’s tip to the negative pole of the battery to see if it lights up. If it does, it indicates a short circuit in your car.
Start pulling your car’s fuses one after another while monitoring the tester light. The moment this light goes out, you have identified your short circuit. Trace the lines that are coming and going to the car fuse box to locate the short circuit.
How to fix a Short Circuit in the Car
There are two ways you can fix this circuit:
- Use multiple layers of electrical tape on the exposed wire to seal it.
- The second option requires you to cut the wire from where it is short and use a connector with male and female connectors. Now crimp these connectors on either side of the affected wire. Keep monitoring the circuit with the tester while connecting the wire.
- Carefully replace the fuse and test the circuit again to see if it is working fine.
Before attempting any DIY, make sure you have the right training and tools. You can find all the tools and auto accessories on sale in Dubai required for the aforementioned process. In case the damage is irreparable, it is better to look for another car. You can find several used cars for sale in Dubai that will fit your requirements.
For more guides on car maintenance and repairs, stay tuned to UAE’s top cars blog.