Drain Test

WARNING: DO NOT ATTEMPT THIS TEST ON A LEAD-ACID BATTERY THAT HAS RECENTLY BEEN RECHARGED.

CAUTION: 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.
- Do not start the vehicle with a clip-on cable. 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.







1. Insert the test leads in the input terminals shown.
2. Turn switch to mA/A dc.
3. Disconnect battery terminal and touch probes as shown.
4. isolate circuit causing current drain by pulling out one fuse after another while reading the display.
5. Current reading will drop when the fuse on the bad circuit is pulled.
6. Reinstall fuse and test components (including connectors) of that circuit to find defective component(s).

Typically, a drain of approximately 1 amp can be attributed to an interior lamp or a malfunctioning electronic component staying on continually. Other component failures or wiring shorts may be located by selectively pulling fuses to pinpoint the location of the current drain. When the current drain is found, the meter reading will fall to an acceptable level. If the short is still not located after checking all the fuses, the drain may be due to the generator.

TEST CONCLUSION
The current reading (current drain) should be less than 0.05 amp. If it exceeds 0.05 amp after a few minutes, and if this drain did not show in previous tests, the drain is most likely caused by a malfunctioning electronic component. As in previous tests, remove the fuses in the power distribution box and instrument panel fuse panel one at a time to locate the problem circuit.