Electrical problems are usually the least favorite thing for mechanics, especially DIY mechanics, to troubleshoot. They’re often tedious to find and sometimes very expensive to fix.
Most battery drains are one of three issues:
- A bad battery. Even a new battery can have problems because of manufacture or defects.
- A bad charging system. Whether it’s a faulty alternator or a bad connection between the alternator and the battery, things can and do go wrong with the system that keeps your battery charged.
- Electrical fault. This can be anywhere in the vehicle that electricity flows from headlamps to dashboard controls.
Finding the drain begins with simple trace routes from one component to the next, starting at the begin point and going all the way through to the end. The beginning will always be the vehicle’s battery and the end will usually be the keyswitch or the component(s) in question. Starting with a full test of the UPS batteries , alternator, and charging system (all the stuff in between those two parts) is a good place to begin and these tests can be done at most auto parts stores free of charge.
Usual suspects include stereos, aftermarket add-ons, bad fuses, and shorted bulbs.