Went to start the jeep this morning and got nothing. Here is what Ive discovered. The battery has 12.3 Volts with the key off, when i get in the car dome lights work, key buzzer works. As soon as I put the key in the on position the dome light dims, and I get no radio, locks, windows, ect...

With the jeep in the on position I get somewhere around 3-5 volts at the battery, as soon as I turn the key off it takes a few seconds and voltage jumps back up to 12+

What could be causing a massive voltage loss just keying the vehicle on?

 

a bad ground somewhere? Or a short in another location?

 

Here is some more info and readings showing the drop. Odd thing is the vehicle will not recover to 12V until the door is shut, but opening and closing the door do not affect the voltage by itself. IF you leave the door closed when you key off it goes back to 12 volts, not quickly but within a few seconds.

It was doing a similar thing a while back and we changed the terminals and it seems to have went away.

Car Off, Doors Shut
http://www.flickr.com/photos/31401781@N00/4878453789/
Door Open
http://www.flickr.com/photos/31401781@N00/4879062830/
Key to first position, Door Open
http://www.flickr.com/photos/31401781@N00/4879062880/
Key On, Door Open
http://www.flickr.com/photos/31401781@N00/4878453933/
Key Off, Door Open
http://www.flickr.com/photos/31401781@N00/4879062962/
Key Off, Door Shut
http://www.flickr.com/photos/31401781@N00/4879062994/

 

This might help
It does sound like you have a short somewhere in the system

http://www.ifitjams.com/starting.htm

 

Well I pulled the terminals and cleaned them, popped them back on and not i get radio ect... when on and a click when trying to start. So bad connection somewhere it seems, ive got the battery on the charger and im gonna give it an hour or so to charge up and see where it stands after that.

 

Have you hit any decent bumps lately or attached/reattached anything that would have had a ground on it? Sounds like you have a bad battery connection to me now though.
I could be wrong though. Maybe check you battery's ground and the connection from the positive terminal into the ignition block?

 

I haven't touched the thing since I put new terminals on. I cleaned both ends of the positive cable to the starter I will check the ground cables also. But right now the battery is at 10v so its gonna be on the charger for a bit.

 

Well im pretty sure its a bad battery, I pulled the battery put the charger on it and when it said it was full, I was only reading 10.5 volts now. Not surprised the batter was MFG in 07 so its 3 years old and its a 3 yr warranty battery.... go figure....

 

You need a battery.

 

yep tossed a spare in there and she fired right up.

 

I had that same problem my ended up being the blower for heater(SHORT)