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POWER CIRCUITRY AND PARASITIC DRAW TEST GUIDELINES
The parasitic draw test is a procedure used to pinpoint the source of severe
voltage draws in electrical systems due to a short in the circuitry.
Specific Tool Required:
Digital Multimeter
PARASITIC DRAW TEST PROCEDURE:
Before beginning, ensure that electrical system is entirely disabled by verifying that
ignition cylinder is in OFF position and keys removed, and that the vehicle kill switch is
in the NO RUN position. If the vehicle is equipped with a theft-deterrent/remote-start
system, please ensure that it is disarmed.
• Disconnect Negative (-) battery terminal.
• Set multimeter to the 25 MILLIAMPS DC (mA DC) setting. Complete circuit
between negative cable and battery by placing the multimeter IN SERIES, with
the POSITIVE test lead connected to the NEGATIVE CABLE, and the
NEGATIVE test lead connected to the NEGATIVE BATTERY TERMINAL.
In a properly operating electrical system, the multimeter will read well under 50 mA.
If the draw is greater, there is a parasitic draw.
• Keeping the multimeter connected IN SERIES, begin removing components
from the loop by disconnecting the pigtails, one at a time. (In some cases, such as
the instrument cluster, it will be necessary to disconnect multiple pigtails in order
to accurately remove the component from the loop).
When the problematic component is removed from the loop, the multimeter reading will
immediately fall to within acceptable range.
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