A battery that goes flat overnight is not necessarily defective. The cause may be parasitic current from a module that does not sleep, a hidden lamp, an aftermarket accessory or a communication network that remains active.
To find it, we measure current after the vehicle completes its shutdown cycle. This may take time because many control units continue operating for several minutes.
We then isolate circuits and identify which module wakes the others. Pulling fuses without a method can erase clues, activate modules or temporarily hide the fault.
Once the cause is found, we also check the battery and charging system so two separate problems are not confused.
