Diagnostic Machine/Jeep wont start

[jeeptastic]

Hey Guys

My Jeep's battery is toast. I can boost my Jeep and get it running but then as soon as I turn it off and it sits the the battery is completely dead. The Alternator is about five or six months old and the battery is about a year old. There is something that keeps draining my battery. My lights are off, interior light is off, radio is off, there is nothing that I can see that is draining my battery. Does anyone have or know anyone that has a diagnostic machine that I can bring my Jeep to tomorrow night and see why it wont start?

I am pretty sure its called a Diagnostic Machine. If its not called that what is it called?

Thanks Richard

[jkrubi]

when you shut the jeep off will it re-start right away?  Are you sure that something is draining the battery? how old is the battery?  After you get it running and shut it off try taking the +terminal off, how big of a spark?   If nothing is on there should be almost no spark or none.  If there is a spark start taking out fuses till it stops, then look in that circuit for a short.  A diagnostic machine will not help it will probly only tell you if the charging system is working or not.  You can check your own charging system with a multi meter, start the jeep and turn on all accesory ie heater fan headlights any other thing that draws lots of power, and the system should still be above 12.5 v to 13.5 v or about that.  Know what your battery volts are befor you start so when its running you know if the system is charging. 

[cLAY]

Check your brake lights, its a long shot but I've seen it happen before.

Switch on pedal for brakelights sticks when you park and the brakelights stay on even with out you in the vehicle draining the battery.

Also get the battery load checked, lots of places will do this for free. You can have a battery show 12v but then totally die off when a load is applied. I know you said its a year old but things happen....

[BBD]

using a volt meter(multimeter) shut down the jeep. wait 15-20 min for all modules to go to sleep. volt meter on battery should rear under .5mV(I think) if you are reading anything over that, there is a parasidic draw on the battery. start pulling fuses until the volts go under .5mV. when that happens you should easily be able to find what is staying on and draining your battery.

[Bnine]

Easier then all of this.

Multimeter the battery and watch for the voltage to drop with the vehicle off.

Once confirmed, disco the battery and preform the same test. If the voltage drops the battery is shorted internally and needs to be replaced.

You dont need a meter to test for draw, a test light to bridge the negative will confirm that, but honestly the most common issue is a bad battery.

Start at the battery. If that doesnt prove to be the issue, come back for more suggestions.

[jeeptastic]

Hi Guys

I just wanted to thank you for your advice. I tried everything you guys said and in the end the battery still had a charge and I was able to get it going again and now everything seems to be working again.

Thanks again.

[Justink]

Have you recently wired in a stereo or subs?  Thats what did it to my battery.

[jeeptastic]

Nope I added my stereo 9 years ago. I have no idea what happened. I might run it down to Lemon Aid Jay tomorrow and see what he says.

[Justink]

Nope I added my stereo 9 years ago. I have no idea what happened. I might run it down to Lemon Aid Jay tomorrow and see what he says.

So does that mean your still rockin a tape deck?