CAUSES OF EXCESSIVE CURRENT DRAIN
(THIS IS A GENERAL IDEA OF WHAT MIGHT DRAIN THE BATTERY, CERTAINS THINGS ARE NOT SPECIFIC TO YOUR VEHICLE.)
Causes of excessive current drain in late model vehicles include things like lights that remain on (trunk and hood lights, interior lights, brake lights, etc.) And also relays that may be stuck on, or modules that are not going to sleep or powering down.
A fuel pump relay that sticks on may keep the fuel pump running after the engine is shut off. A switch or relay that powers a rear window defogger can stick on, pulling current from the battery after the ignition is off.
An accessory such as a DVD player, game console or cell phone charger left plugged into a rear seat power receptacle may be pulling power from the battery. So before you spend a lot of time trying to figure out where the amps are disappearing, check all of the vehicle's power receptacles to see if something is plugged in that may be using power.
To measure current drain without an inductive amp probe:
1. Set the DMM to read milliamps (mA). If the meter is not auto-ranging, select the 100 or 1000 mA scale.
NOTE: the DMM should have a 10 amp fuse in it to protect the meter from possible damage if there is a large current drain on the battery.
2. Plug a battery backup into the cigarette lighter (or attach a backup battery or power supply to the battery cables) to protect KAM while disconnecting the battery cable.
3. Disconnect one of the battery cables and connect the DMM test leads to the cable and battery post.
4. Unplug the battery backup and note the current reading on the DMM.
NOTE: Do NOT remove the DMM test leads until you have plugged the battery backup in the cigarette lighter or reconnected the battery backup to the battery cables, otherwise you will lose the KAM if power is disrupted.
FINDING THE CAUSE OF THE CURRENT DRAIN
It's time to start pulling fuses and relays to find the fault.
Let me know wich fuse, or relay you pull that stop the drain.
Sunday, November 8th, 2009 AT 6:48 PM