msvphoto

Our 2001 2WD XL Supercab (4.6 automatic) is draining the battery down to a no start level if it sits for more than a week or two. The alternator is fairly new (rebuilt, so not so new perhaps). The battery is a new Costco/Kirkland replacement (a month or so ago now) for one that was only charging to around 11.8v. Charge voltage is ~14.6.

If I remove the hood light bulb and measure drain I am getting ~260ma. I have read that the GEM needs to time out before you can get a true drain reading, and I have seen some procedures that describe leaving the hood open, the battery circuit not interrupted (leave the DVM connected?), etc. for 45 minutes or so for the GEM to go to sleep and then measure the parasitic drain.

Can someone here enlighten me further to this procedure? I am assuming that the GEM is actually going to sleep as it should since the 260ma drain would likely kill the battery in a day or two and it does last longer than that. However, there does seem like there may be more drain than there should be and I would like to have a better understanding how to measure drain with the GEM sleeping (and how to confirm it is going to sleep).

I had a recent fuel pump failure and in the course of troubleshooting was looking for moisture around the GEM and fuse panel from windshield leaks--none found but I will check this again also.

tansupercrew

35ma is acceptable draw. Hook the leads up to the battery with vise grips and let it sit for 20 min. That should be sure everything is asleep. Then start pulling fuses.

msvphoto

Great tip on the vice grips! Should I leave the hood light bulb pulled out? I imagine the GEM should go to sleep either way, as long as nothing changes state (by opening the door, the hood, etc. to "wake it up").

sledmanjones

Here's what I did....

Pull out the hood light so it's not a draw. Also flip the door latch with a screwdriver, so you can pull the fuses in the inside fusebox, as well as the underhood box. Clamp your meter inline with the negative cable, and go inside and relax for 45 minutes. At least thats how long it takes for my truck to go to sleep. Then you can begin to pull fuses. A Ford tech I know reminded me not to re-install each fuse, right after pulling it, as that may re-start any "background" process, which would cause un-identified draw. So you may want to follow the fuse location/size map in your owners manual, or found online.

My issue was a poor ground condition. The ground strap directly under the passenger footwell was corroded, which caused the ground to be interrupted intermittently, which was "waking up" the computer. I found that solution online, probably here even, and sure enough, after I replaced all my ground straps with larger ones, and I added one from engine to frame, it seems to stay fully charged.

With any electrical issue in an older truck, there are so many possible problem areas, it never hurts to check anything you can.

msvphoto

Thanks to the Vice Grips idea (brilliant!) I was able to measure drain with the GEM sleeping and it is 70ma (measured with a fairly high end Fluke meter). I'm thinking now it is perhaps the aftermarket stereo (installed by/for the previous owner. There is an older high end Pioneer in-dash and some kind of sub in a center console enclosure (powered? dunno).

I'm not sure if I want to spend anymore troubleshooting time on this since the parasitic draw is close to acceptable. I'm thinking just get a solar trickle charger and be done with it for now. This hadn't been a problem until my wife curtailed her landscaping business somewhat, resulting in the truck sitting for longer periods of time. If it were driven every few days this would not be a problem at all. If it sits for a couple of weeks, not so good.

Given my recent intermittent no start issues (seemingly fixed with a new fuel pump) I am going to re-explore the possibility of windshield leaks and monitor that as well.

UKblue150

Did you ever locate what was puiling? i have a 2003 and i'm out of ideas of things that would pull a draw. I have a 10amp draw, fuses, alternator, battery, etc are all fine.