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Something draining battery

2K views 2 replies 2 participants last post by  JerryofWV 
#1 ·
Last year I had a problem with the battery going dead in my 2012 Liberty. The dealer checked it and said it needed a new battery. They replaced it under warranty.

When I leave it parked for a couple of weeks without driving it the battery is completely dead. I can charge it and it works fine unless I don't start it for a couple weeks. It's out of warranty now.

Any ideas on what I can check?
 
#2 · (Edited)
The battery will have a natural draining of its charge when not used, but being discharged in two/three weeks is a bit too quick.Did you check for the obvious things like internal lights which stay on, or radio which doesn´t switch off (glovebox light as well)?
If no obvious reason found, you will need to start trouble shooting. There are several computers which will have a constant feeding from the battery for the internal memory, so there will allways be some drain. But then you are talking about a current draw of 100 mA or so. Some computers can stay powered for some time after switching the ignition of. I would start removing the IOD fuse (ignition-off draw fuse, # 27 in the integrated power module under the hood) and put a DVM (digital volt meter) in ampere position between the two fuse slots. You can start in the highest position and switch down when the currents go lower. After ignition off, some computers will go to sleep after 5 minutes, but some even after 30 minutes. Don´t touch the doors, because that will wake up some computer and increase the current draw.
Seems that the sunroof module already caused many problems of unwanted battery drain, so you could pull the fuse of the sunroof module after letting all the modules go to sleep and see if the current draw reduces.
 
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