With Voltmeter Test Procedure

This test requires a digital volt-ohmmeter with an appropriate low voltage scale such as Rotunda 88 Digital Multimeter 105-R0053 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 compartment lamp is turning off properly, disconnect the bulb.
2. Check battery voltage. If voltage is under 11.5 volts, charge the battery to above 11.5 volts.
3. Disconnect battery ground cable.

NOTE: When the battery has been disconnected and reconnected, some abnormal drive symptoms may occur while the Powertrain Control Module (PCM) relearns its adaptive strategy. The vehicle may need to be driven 16 km (10 miles) or more to relearn the strategy.

4. Connect shunt.

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

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.

Test Conclusion
The current reading (current drain) should be less than 0.05 amps. If the reading is between 0.2 and 0.9, a possible drain may be a vehicle lamp (glove compartment. compartment lamp, luggage compartment lamp, etc.) that does not turn off. If the problem is not a lamp, remove the fuses from the fuse holder 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.