Do it yourself
Frequently asked questions about cars and motorcycles
Car tutorial (Do it yourself) Motorcycle tutorial (Do it yourself) Frequently Asked Questions

Types of Positive Cables in Cars

Model: (Various brands) Various
Part: Checks and maintenance

There are different types of positive cables in a car: those that are always live (even with the engine off) that power devices that must always function, such as courtesy lights, radio memory, central locking module, and hazard lights. Then there are those known as 'switched live', which are active only with the ignition on, and temporarily deactivate during starting to avoid current spikes, such as the radio, windscreen wipers, interior lights, and on some models, even the radiator fan. There are also 'engine live' cables, which are managed by the control unit, active only with the ignition on but do not turn off during starting. They power critical engine components, such as injectors, coils, sensors, and solenoids. Then there is the positive for warning lights and dashboard, which is similar to the switched live but does not turn off during starting. It is important to know this difference to avoid short circuits or damage to components and to prevent draining the battery (for example, with the radio always powered). To connect devices to the correct cable, how do you identify a switched live cable? With a multimeter: with the ignition off, voltage is 0V; with the ignition on, voltage is 12V. During starting, the voltage drops to 0, then reactivates.

Posted on 2 April 2026 by ScegliAuto

Video tutorial

Related tutorials

How to install the backup camera
How to install the backup camera
(Various brands) Various This guide is about the general installation of an Android backup camera: we will see two identical AV cables, one connected to the AV input of the d…
How to install the Force Master control unit.
How to install the Force Master control unit.
(Various brands) Various Today we will explain how to install the Force Master 2 control unit. The control unit on these types of scooters is located in the compartment under…
How to Reset All ECUs and Control Modules in Your Car
How to Reset All ECUs and Control Modules in Your Car
(Various brands) Various In this video, we will see how to reset all the control units in your vehicle; this method is valid for almost all cars in general and corrects most …

Other guides you may be interested in

    Frequently Asked Questions

    • Vari - What does it mean when the message "insp" appears on a car? Read answer
    • Vari - What problems does the Kymco Downtown 300i have? Read answer

How to Replace the Cabin Filter on the Opel Grandland X

If you own an Opel Grandland X and want to know the steps to replace the cabin air filter, carefully read the following guide and follow the described steps. First, enter the vehicle and go to the passenger side. Then, locate the box containing the air filter in the lower side area of the dashboard. Remove the cover of the box and finally replace the old filter with the new one. Refit the cover, and you are done.

Watch the video!


by ScegliAuto

More videos