BMW For Beginners: How To Find An Electrical Short Circuit

When your car starts emitting strange noises or doesn’t seem to be running right, it’s time to take it in for a diagnostic. One common issue that can cause problems is an electrical short circuit.

This problem can be challenging to track down on your own, which is why it’s essential to take your car to a reliable service like BMW of Fort Walton Beach.

In this blog post, we’ll disclose how you can try to locate an electrical short circuit in your car.

What Types of Circuits Does My Car Have?

The answer would be two: the sensor and the actuator circuit.

A classic example of the sensor circuit, the engine coolant temperature, would feature the wiring between the sensor, ECT, and the engine control module, or ECM. The ECM sends voltage to the ECT, which changes according to temperature levels. If the engine is hot, resistance is weak, and a higher voltage gets back to the ECM – and the opposite occurs when the engine is cold.

On the other hand, an actuator circuit can be demonstrated with an example from your car’s headlights. The wiring from the headlight switch to the headlights is an actuator circuit. When you turn on your headlights, a relay closes and provides power from the battery to the headlights.

What Are the Different Types of Short Circuits?

For electrical short circuits in a car, you’ll find two types: short to power and short to ground.

Short to power

This type involves chafed or cut wires touching each other, enabling the current to flow where it’s not supposed to. A common symptom of this short is your reverse lights turning on if you step on the brakes or a flow of current to the horn when you turn on the headlights.

Short to ground

“Ground” here refers to the body or chassis of the car. This short happens when a hot wire (one that has current flowing through it) comes in contact with the body or chassis of the vehicle. A typical indicator is a blown headlight fuse, preventing overheating but knocking out the headlight.

How Do I Find a Short Circuit in My Car?

Caution: If you’re not familiar with car electronics, it is best to leave this to the experts!

This procedure takes a series of steps but, if done correctly, can help you find a short circuit in your car’s electrical system.

1. Gather your gear. To locate the short safely, you’ll need a test light or multimeter, insulated wire, electrical tape, and a pair of pliers.
2. Find the blown fuse. You want to know where its wires go, what connectors they go through, and what color they are.
3. Remove the fuse. Grab your multimeter or test light and connect it across the terminals of the fuse socket.
4. Move to the battery. Disconnect the battery positive terminal and instead set the positive probe on the load side of the fuse. You’ll then clamp the negative probe to the battery’s negative.
5. Read the signs. If you’re using a test light, it should illuminate if you’ve found a short circuit. In the case of a multimeter, which measures continuity, you should hear a beeping sound.

Conclusion

While it’s essential to stay informed about your car, you should not attempt to fix an electrical short circuit on your own. Bring your vehicle to BMW of Fort Walton Beach, and we’ll take care of it for you.

We serve Niceville, FL, to help you get the most out of your vehicle. Schedule a service appointment today!