Mechanics

JEEP CHEROKEE BATTERY PROBLEM

1997 Jeep Cherokee • 70,000 miles

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
Avatar
Depayens
October 30, 2012.




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.

Mhpautos
Oct 30, 2012.
Thanks mhpautos, I will let you know how this goes.

Tiny
Depayens
Oct 30, 2012.
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.

Rivermikerat
Oct 31, 2012.
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.

Tiny
Depayens
Nov 3, 2012.
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.

Rivermikerat
Nov 3, 2012.
Ok, everything looks fine around the ignition switch.

What next?

Tiny
Depayens
Nov 3, 2012.
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?
AD

Rivermikerat
Nov 3, 2012.
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?

Tiny
Depayens
Nov 5, 2012.
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).

Rivermikerat
Nov 5, 2012.
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).

Tiny
Depayens
Nov 6, 2012.

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