With Voltmeter Test Procedure
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.
- Turn the ignition off and make sure there are no electrical loads on. After determining the compartment lamp is turning off properly, disconnect the engine compartment lamp miniature bulb.
- Check the battery voltage. If the voltage is under 11.5 volts, charge the battery to above 11.5 volts.
- Disconnect the battery ground cable.
- Connect the shunt assembly
- Connect the voltmeter leads to shunt as shown. With this size shunt (50 mV = 50 amps) and voltmeter, a direct current drain measurement can be made.
- The current reading (current drain) should be less than 0.05 amps. If it exceeds 0.05 amps it indicates a constant current drain which could cause a discharged battery. Possible sources of current drain may be a vehicle lamp (glove compartment, underhood, etc.) that does not turn off. If the problem is not a lamp, remove the fuses from the interior fuse junction panel one at a time until the cause of the drain is located. If drain is still undetermined, remove fuses one at a time at the engine compartment fuse junction panels to find the problem circuit.
CAUTION:
Do not crank the engine, it could destroy the shunt. Also do not use the shunt to measure starting currents.