I have a .25 amp drain on the battery overnight on a 2001 Ranger 2.5 manual 2 wheel drive. I’ve isolated it to the GEM module, when I disconnect it the current drain disappears. Is there any way to check the module or adjacent circuits it controls.
Yes, I am sure there is a way to check it but not for the shade-tree mechanic. Ford obviously can as can the supplier who built it. There are people who repair these things but finding one may be tough.
Just go online and see if you can find an EBay seller with used ones and swap it out. I found used ones for $50-$60 and remanufactured ones for $104
Is a .25 amp drain too much for this one component?
Waaaaay too much. The total draw from ALL the “keep alives” should be under 0.085 amps (or 85 milliamps) if you want the car to start after sitting for any amount of time.
I had this problem on a Corvette I owned. The BCM/dash module had a shorted trace that drew about 250 mV. It would draw down the battery below start after about 4 days. A local repair shop fixed it for about $400 25 years ago. A new one would have been more than $2500 from Chevy.
Is the unit used based on amps per unit of time? Amps per hour? So .25 means 24 X .25 = 6 amps in a day?
Your math is correct but the results have the wrong units. 0.25 amps times 24 hours is 6 amp-hours. In 3 days you battery is drawn down by 18 amp hours. Your battery may be rated at 50 amp hours which means the battery is now at only 65% capacity on a new battery.
More commonly batteries are rated for “reserve capacity” or how many minutes the battery can supply 25 amps of current before the voltage falls below 10.5 volts. And that is low enough to prevent starting.If you multiply he reserve capacity minutes by 0.4167 that gives you the amp-hours of the battery.
Typical reserve capacity for a group 75 battery would be about 100 minutes reserve or 42 amp hours so after 3 days of 0.25 amp draw, you’d only have 57% left with a nearly new battery. Less with an old one.
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Just a little googling on it. I don’t know anything about it but there is a good video on replacing it. Seems like it is a common problem causing electrical issues and parasitic drain. May be the wiring though or something else. There is also a memory relay or something that is supposed to shut things down. Another video showed the huge array of test equipment to check on at the Ford dealer. The other issue is that it’s not clear if it needs to be programmed by Ford or not. Depends on the model and year I guess. If not, just plug and play but sounds like there were at least three different ones used so gotta get the right one. They are only around $100 for a quality one so might be worth while just swapping it out for the cost of a diagnosis. I guess I’d want to first talk to Ford or a good supplier to determine which one exactly and whether programming is needed. Also I’d look into that keep alive relay.
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After checking on line I’ve found that
After 15 minutes the GEM unit goes
Into sleep mode. I’ve checked the hub
Current drain after 15 min and it’s less
Than 10 mils, so maybe my battery is
Bad so I will do a load test next.I
Not to steer you in the wrong direction, but I had an electronic level control that was intermittent and drove me nuts. Battery went dead while parked and couldn’t find anything wrong, then all of a sudden the test light lit up like Christmas and all was fine when I disconnected the ELC. So yeah could be battery or the the thing is messing with your head.
If by “10 mils” you mean 10 milliamp parasitic draw, then you don’t have a problem, as far as that’s concerned
Just how old is that battery?
If it’s over 5 years old, just be proactive and replace it . . . consider it maintenance
If it resolves your problem(s), good. If not, more testing is needed
I’m assuming you have/had problems starting the engine in the morning . . . ?
Do you park the truck in the driveway?
If so, what were the outside temperatures?
I just put a head gasket on the engine and the truck sat in the driveway for 4 months prior to that. The battery is older than 5 years so your right in replacing it. But I was concerned about the parasitic when I first measured it after the truck would not turn over the next morning. As a result of research and talking to people like you I’ve determined it was the battery. I really appreciate advice from u guys.
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Bing,
Luckily I disconnected the ELC prior to all the testing and eliminated that unit.
If you’re a Costco member, head over there. They’ll have your battery in stock, and the price is pretty good, lower than Autozone, for example, and with a better warranty.