teddysmith1952

Hi all,

First time poster. My daughters 1997 grand cherokee's battery has been draining and will only hold a charge for about 36-48 hours. We replaced the battery 6 months ago and just had it checked out and it is good.

It's been awhile since I've got into this sort of stuff but I whipped out my trusty multimeter and did some checking. I disconnected the postive cable, connected my multimeter to the post and cable and sure enough it was reading 188 milliamps of pull. I believe about 30 milliamps is normal for the clock, etc. I then proceeded to pull each fuse one at a time and when I pulled the 50A fuse, it dropped down to near 0.

According to my fuse box legend, this fuse (position 11 in the fuse box panel) is in line for the memory functions, power window, power door locks,power mirrors, remote keyless entry and the trailer tow package which we do not have.

My daughter told me that a few months ago the power door lock would not open the passenger side door which had to be opened by the internal latch of with the key from the outside. With this said, I definately see a connection between the battery drain (related to the power locks) and the door not opening when the power door lock switch is hit.

Any ideas on where to start would be much appreciated.

Thanks,

teddysmith1952

Well, I guess this forum is no longer operational. Dang.

Hymie

I would agree that 188mA seems a high current drain, but with the amount of electronics on modern vehicles, this might be within the normal range, after all it is only just over 2 Watts.

My 2000 Grand Cherokee is fitted with a 74Ah battery, theoretically it would take nearly 400 hours (over 16 days) to drain the battery at that rate. Even so, that’s 4.5Ah lost per day – having identified possible circuits responsible for the drain, I would start disconnecting things to isolate the drain further (if there are any fuses further down the line – pull those first).

If it proves to be the memory functions or the remote keyless entry – then I would suspect it to be a normal battery drain rate for your vehicle.

Hymie

More thoughts on your problem:-

At 188mA for 48 hours is less than a 10Ah drain from the battery – this should hardly be noticeable on a good (60Ah+) battery.

It may be that you are measuring a low drain figure due to the impedance of your multimeter. Cheap meters suffer from having a high resistance (on low current ranges). At 188mA, a 12 Volt circuit has a resistance of 64Ω. If the meter has a resistance of 40 Ω, then without the meter in circuit, the current drain would be 500mA (or 6 Watts). This would lead me to suspect a bulb on, which should not be.

babycare814

I have found a problem that helped me and wanted to pass it along to each of you. The battery was draining over night enless you pulled the 50 amp fuse under the hood. We traced the problem to the rear window motor and tow package. We took the fuses out and so far the battery stayed charged. At least for the first night. If that does not do it for me, I will let you know. I just thought it might help someone else too.

ol"blue

Welcome to CF, and thanks for sharing that info.