With Voltmeter

This test requires a digital volt-ohmmeter with an appropriate low voltage scale such as Rotunda 73 Digital Multimeter 105-00051 or equivalent. The meter must read within 0.01 millivolt. Also required is a shunt assembly.

1. Turn ignition switch to the OFF position and make sure there are no electrical loads. After determining the underhood lamp is turning off properly, disconnect the lamp.
2. Check battery voltage. If voltage is under 11.5 volts, charge the battery to above 11.5.
   NOTE: When the battery has been disconnected and reconnected, some abnormal drive symptoms may occur while the powertrain control module (PCM) (12A650) relearns its adaptive strategy. The vehicle may need to be driven 10 miles or more to relearn the strategy.
3. Disconnect battery ground cable (14301).
   CAUTION:

   Do not crank the engine; it could destroy the shunt. Also do not use the shunt to measure starting currents. 

4. Connect shunt assembly.
5. Set volt-ohmmeter to 200 or 300 mV scale for an accurate reading (must be within 0.01 millivolt).
6. Connect meter leads to shunt. With this size shunt (50 mV = 50 amps) and meter, a direct current drain measurement can be made.

The current reading (current drain) should be less than 0.05 amps. If the reading is between 0.2 and 0.9 amp, a possible drain may be a vehicle lamp (glove compartment, underhood, luggage compartment, etc.) that does not turn off. If the problem is not a lamp, remove the fuses one at a time until the cause of the drain is located. If still undetermined, disconnect leads at starter relay one at a time to find the problem circuit.