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i've got a 97 F350 7.3 Power Stroke and both batteries are going dead (draining) after being confirmed good and recharged on three different occasions. The alternator was recently replaced. Has anyone had experience with this? Could it be a short in the electrical system, bad or loose cables??
Last edited by lfernandez155; Nov 2, 2017 at 01:06 PM.
Reason: Incomplete problem description
Sounds like a "parasitic drain" or "phantom" load. Possibly a defective alternator, or some component or device that isn't shutting down properly. The trick is to isolate it. Basically an ammeter is placed in series with a battery cable and terminal and measure for excessive current draw after shutdown. It's tricky sometimes, as different modules or gee-gaws can remain energized for up to an hour after shutdown. So you'll have to set aside some time for this. And even opening a door can "wake up" the computer meaning start over. Usually anything over 50 to 75 mA is considered excessive. Start pulling fuses and relays and such to try and determine what's going on and track it down.
Could try disconnecting alternator and see if the battery holds charge as a start, I suppose. Welcome to FTE btw.
Yeah its draining in a matter of weeks. maybe 2 weeks or three So this has been going on for maybe since august and i think its the 4th time. Yeah 4th time. Its not running right now because of this. Thanks for the tips ...I'll check both suggestions.. bad relay and try to isolate the drain.
Two or three weeks is a long time for sure. Check the simple things such as the glove box light staying ON when closed. Yep, it happened to me. I would think if it was the GPR that would drain the battery in hours, not weeks.
Earlier this year I picked up my 99 in Arizona and it had a similar issue. Sitting for a week or two the batteries were dead. Everybody blamed some parasitic draw from some unknown sources. Drove it back to Oregon and took it to a tire/battery dealer and had both load tested. Passenger side was at 20% and drivers side at 80%. Had them replace both with new 850 CCA and no problems since.
Don't know how your batteries were tested but just a volt meter doesn't cut it, get them load tested if possible. Most shops will do it for free as they want you to buy their product. Also if one battery shows bad, with the load test, it is recommended to replace both at the same time, especially if both are the same age.
If you are driving during that period and it is draining the batteries then I would look at batteries and or alt. You driving or is truck setting for 3 wk?
Good question yeah it's been driven during those drains. Alternator was first thing looked at and replaced after first drain. So now having to look deeper into cause.