A battery drain refers to any system or device within a car that is draining power out of the car's battery. Although some systems are designed to run off of the car battery, like the cigarette lighter and the digital clock, they do not require a large amount of power. When a system within the car is malfunctioning it can quickly drain the battery....
M/F Search the major car functions in order to begin ruling out some of the potential causes of the battery drain. Check that the headlights were not left on unintentionally. Also, check that all of the battery cables are tight.
M/F Narrow the search further by checking to see if the battery has a charge. It is important to figure out if the battery is holding any charge at all. If the headlights were not left on, the cables are tight, and the battery can hold a charge, then the drain is most likely in the car's electrical system.
M/F Open the car hood and disconnect the negative battery cable from the battery. Use a flashlight or headlamp if the vehicle is not located in a well-lit area. In order to check the electrical system a test light must be obtained.
M/F Place the test light in the circuit between the negative terminal of the battery and the negative battery cable. One end of the test light should be connected to the negative terminal while the other end is attached the battery cable. The test light will assist in determining the exact portion of the electrical system that is causing the battery to drain.
M/F Observe the strength of the test light's glow. A faint glow is normal, while a bright glow indicates that there is a battery drain.
M/F Locate the fuse panel and begin to remove one fuse at a time. If the test light stays lit when a fuse is removed, then reinstall that fuse and take out the next one. When a fuse is removed and the test light goes off, the location of the battery drain will have been located.
M/F Replace the faulty fuse in order to solve the battery drain. In some cases the battery may need to be charge in order for it to recover from the loss in power.