Battery - Drain Testing
Check for current drains on the battery in excess of 50 milliamps with all the electrical accessories off and the vehicle at rest. Current drains can be tested with the following procedure.
WARNING:
- Do not attempt this test on a lead-acid battery that has recently been recharged. Explosive gases can cause personal injury.
CAUTION:
- To prevent damage to the meter, do not crank the engine or operate accessories that draw more than 10A.
NOTE:
- Many computers draw 10 mA or more continuously.
- Use an in-line ammeter between the battery positive or negative post and its respective cable.
- Turn the switch to mA/A dc.
- Disconnect the battery terminal and touch the probes.
- Isolate the circuit causing the current drain by pulling out one fuse after another from the fuse junction panel while reading the display.
- The current reading will drop when the fuse on the bad circuit is pulled.
- Reinstall the fuse and test the components (including connectors) of that circuit to find the defective component(s).
- The current reading (current drain) should be less than 0.05 amp. If current drain exceeds 0.05 amp, a constant current drain is present.
- Compartments (Underhood, glove compartment and luggage compartment lamps) that do not shut off properly are all possible sources of current drain.
- If the drain is not caused by a vehicle lamp, remove the fuses from the interior fuse junction panel one at a time, until the cause of the drain is located.
- If the drain is still undetermined, remove the fuses one at a time at the power distribution box to find the problem circuit.