I think i might have a battery problem or a short somewhere that is draining my battery. How do you measure current drawon thebattery while the vehicle is not running.

Hardwarz

99 Chevy Tahoe, Vortec 350, 4x4, 4 door with tow package.

 

To measure current drain using a Digital Multimeter:
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: The chips that store certain settings and learned information are called the "Keep Alive Memory" (KAM).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.

 

I followed the instructions (more or less, the battery was disconnected already)

Having my meter set to 200mA, I have a current draw of 0.4mA. What's normal current draw?

Thanks for your help.

Hardwarz

 

Some Advance Auto Parts stores have a new machine that checks Bat., Alt., Starter, and current draw. The store I work at has one and it will do a print out to show you exactly what is going on.

 

.4ma is not a large draw at all. Your draw will also vary from vehicle to vehicle and for different trim levels. ZX would probably know what it is. When you first shut the vehicle off there is a higher draw for systems that have not shut down yet. You should usually check for draw 24 hours after the vehicle is shut off to ensure all systems are off.

with only .4ma I would put a charger on the battery and fully charge it. After it's fully charged, remove the charger forat least 20 minutesand use your multimeter in the voltage setting to check the battery. Positive to positive, negative to negative. Here's a photo for the state of the battery. The percentage on the right is the battery life. I would bet the battery is bad.