Parasitic Current Drain Testing With an Ammeter

PARASITIC CURRENT DRAIN TESTING WITH AN AMMETER

1. Turn the ignition and all accessories off.

2. Disconnect the cable from the negative battery terminal.

3. Follow the manufacturers instructions for the multimeter or ammeter being used. This could involve plugging the leads into different locations on a multimeter and changing the scale to read amperage. On some testers you should start on the 10 AMP scale setting, and after verifying that the current drain is less than two milliamps, set the scale to 200 milliamps or 20 milliamps.

4. Sedan:
a. Install the ammeter between the negative cable and the negative battery terminal so that it is in series. Read the parasitic current drain from the battery.

Coupe:
b. Install a jumper wire between the negative battery cable and negative battery terminal. While the jumper is installed, connect the leads of the ammeter to the battery negative cable and the battery negative terminal. This causes the ammeter to be in parallel with the jumper wire. After 10 seconds, remove the jumper wire and read the parasitic current drain from the battery.

NOTE: Step 4b must be performed on the Coupe before attempting to measure the parasitic current draw from the battery.

5. To find the source of the excessive load, start removing the fuses in a systematic way. When the voltage drops across the tester, the circuit or circuits protected by that fuse is the source of the current drain. Repair the circuit and perform the parasitic load test again to verify the repair.

NOTE: The ignition key must be removed from the cylinder before parasitic load testing. The key-minder circuit, activated by the key cylinder switch when the key is in the ignition cylinder, which adds 20 milliamps of current draw.

NORMAL PARASITIC LOADS
^ PCM 2.2 - 2.5mA
^ Generator 1.0 - 2.0mA
^ Radio 2.8 - 4.3mA
^ ABS 0.1 - 0.3mA
^ Passive restraint 0.1 - 0.2mA
^ Chime/dome lamp module 0.7 - 0.9mA
^ Headlamp door module 0.4 - 0.5mA


TYPICAL UNDESIRED PARASITIC LOADS
^ Park lamps on
^ Headlamps on
^ Dome lamp on
^ Map lights on
^ Cargo lamp on
^ Radio on
^ Cigar lighter on