1997 JEEP CHEROKEE
70,000 MILES
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DEPAYENS
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Hi,

My Jeep:
Cherokee XJ 1997 2.5L turbo diesel.

My problem:
Recently, someone unsuccessfully attempted to steal my Jeep and I had to get a second hand ignition switch installed (from my dealership). Since then, my battery has been draining overnight and things have got worse. My immobiliser has become stuck on. When I unlock the car using the key fob, the 'security' light goes off, but the fuel and battery gauges do not work. Whats worse is, when I try to use the OBD and get the codes, it does not actually do anything (the check engine light never comes on during start). I have got my battery charger on the battery (still connected to the car circuits) at all times as to provide power.

I am totally at my witts end and am out of ideas. Anyone got any suggestions?

Thanks
Oct 30, 2012 at 7:29 AM
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MHPAUTOS
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Start with a current draw test to determine which circuit is drawing down, do this by removing the battery pos (+) terminal and fit an Amp meter between cable and terminal, (do not attempt to start car) with doors closed and key out, check the current draw, if above say .15Amos ans around .25 or higher, start pulling fuses to see which circuit is drawing down, also check that the alternator is not faulty, undo the main alt cable, if the amps drop you will have a blown diode in the rectifier, start here and let me know what you find.
Oct 30, 2012 at 9:06 AM
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DEPAYENS
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Thanks mhpautos, I will let you know how this goes.
Oct 30, 2012 at 10:15 AM
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RIVERMIKERAT
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Also, if you can, check the connections on the secondhand ignition switch. They may have shorted something inside it during the install. Or the bad guys might have during the ripoff attempt.
Oct 31, 2012 at 10:42 PM
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DEPAYENS
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Hi Guys,

I have performed the current measurements with the car in the off state. Interestingly, there only appears to be an initial impulse current (too fast for my ammeter to pick up, I see a minor spark when making contact). The current then drops to near zero.

I have removed the dash and steering wheel covers and will check the ignition switch for shorts.

I will let you know how that goes.
Nov 3, 2012 at 12:41 AM
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RIVERMIKERAT
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Ok. Sounds good. That spark shouldn't be there. With everything off and the door closed, there should only be a very light spark caused by the memory for the stereo and ECM.
Nov 3, 2012 at 12:51 AM
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DEPAYENS
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Ok, everything looks fine around the ignition switch...

What next?
Nov 3, 2012 at 3:08 AM
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RIVERMIKERAT
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Fully charge the battery and have it load tested. See if it holds a charge without being in a circuit.

What is the total draw on the battery with everything but the hood closed and off?
Nov 3, 2012 at 3:08 PM
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DEPAYENS
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I have gone one further and purchased a new battery (old one was 6 years old). Same problem. I have also measured the total draw on the battery with my chip on ammeter and it ranges from 100 - 150 mA.

This is very puzzling!

Should I remove the ignition switch and test it?
Nov 5, 2012 at 10:10 AM
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RIVERMIKERAT
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100-150 mA is next to nothing. That's less than I would expect for stereo and computer memory. That low of a draw is running your battery down overnight? If 100-150mA is running your battery down overnight, either you have the wrong battery (not enough CCA) or a bad battery (not holding a proper charge).
Nov 5, 2012 at 1:11 PM
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DEPAYENS
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Forgetting the battery for the time being, the problem still exists of my immoboliser preventing my car from starting. And for the matter, my OBD system not functioning. This is the real problem... I suspect the battey issue was a coinciding problem, meaning it was on its way out anyway (6 years old).
Nov 6, 2012 at 1:37 AM
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RIVERMIKERAT
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That's quite likely the case.

When you turn the key, what exactly happens? Do you get a clicking? Does it turn over and not start? Can hear the fuel pump powering up for 2 seconds and then shutting down? Find the power lead to the OBD and see if it's getting power. Then make sure the ground for it is in good condition and making solid connection to ground.

Do your remotes do anything at all?
Nov 6, 2012 at 1:53 AM