Help needed with massive battery drain 2007 expedition

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skinnedknuckles

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Hi all, newbie here. just bought a 2007 limited el and it's been great for about 2 months, then all of a sudden, battery goes dead. Did some research and began testing to find there is about a 9 amp draw when there should be just milliamps. I've found that by pulling fuses #5 has about a 6 amp draw and fuse #3 about 1 amp. There is still another 2 amps that are still draining regardless of fuses pulled. Also, relay #55 under the hood makes some strange clicky sounds, but does not alter current draw if I remove it. This has really got me puzzled and don't know where to start. Do I need to take to dealer? The #3 is marked FES, I don't even know what that means. The #5 is very important and I can't drive without it as this fuse controls the shifter and won't go into gear unless it is enabled. The #5 fuse is for; Keypad illumination, 3rd row seat enable,Brake Shift Interlock (BSI). SPDJB, TPMS initiators. I can jump start the car and it runs great and all functions seem to work perfectly, except massive battery drain. When shut off, battery will drain very quickly. Any help at all would be so greatly appreciated. Thanks.
 

Adieu

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~100w then (9 amps by 12 volts)...thats like a laptop or a couple TVs running

Process of elimination, possible candidates by power consumption:

1) somehow shorted HID ballasts or LED drivers for a pair of lights, headlight or foglight (typically these systems are rated 30 to 60 watts per side)

2) amplifier from sound system stuck on?

3) HVAC system

4) maybe just maybe all the processing power of a touchscreen navi & multimedia unit frozen up in its shutdown sequence with all bluetooths etc blazing locked in an attempt to connect to something

5) possibly 3rd row servos (but shouldnt you hear it spinning if it broke a gear and got stuck "on"?), afair they're on some huge fat connection rated up to like 30 or 40 amps so a draw of 10 amps could be feasible


Hmmm...what else? Do you have some sort of keyless fob-only based system or an aftermarket alarm running on a "just keep it in your pocket, no need to do anything else" principle? If yes, check vehicle for a spare fob abandoned somewhere inside, or perhaps in a garage or by the front door if that's really close to the vehicle...also if you do but thats where you always kept em before with no issues, replace the little batteries in all your fobs and remotes that are potentially within range of the vehicle, some idiotic designs stubbornly kick into overdrive trying to maintain connection if a signal is really weak (sorta like phones sometimes heat up and discharge like crazy in areas of spotty reception)


Oh and if you DO have headrest or folddown TVs, a mounted laptop, lightbars, or juryrigged aftermarket headunit stereo/nav/dashcams backup cameras/wifi hotspots/etc, you know what to start unplugging before asking

PS i *know* you mentioned stuff getting run thru specific fuses, but with a used vehicle who knows what somebody mightve hooked up and where....do it yourselfers often splice into whatever power they can find
 
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Bedrck47

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Fuse #5 is also for the 3rd row seats. Make sure the switches are not stuck
Fuse #3 is for the Auxiliary audio module, Satellite radio receiver, DVD player
Relay #55 is the trailer tow relay Check your 7 and 4 pin connectors for any dirt corrosion etc.
 
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Bedrck47

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If possible you may want to disconnect the power feed to the Passenger compartment fuse box and then check to see what power draw you get This way you will be able to know how much power draw is on each fuse block
 
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skinnedknuckles

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thanks so much to all that replied. I think I am over my head with this and have made an appointment at a local shop to diagnose and repair this problem. They told me they have a standard electrical battery/charging system/drain test and that because it is such a large drain/short they should be able to find it, and estimated about 2 hours labor. Sounds very reasonable. I'll post with the findings, in case anyone has similar problems in the future.
 

Bedrck47

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Thanks for the update Let us know the results and how long it took them to fix it.
It may help the next member
 
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skinnedknuckles

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Ok, I was not sure whether to take it to the dealer or a local shop. I brought it to a local repair shop, they sounded good on the phone, have been there a long time, and and have certified tech's. They said they would do a standard battery/charging system/drain tests, etc. They were busy and asked me to leave the car for the day, offered to drive me home, but I decided to walk, about a mile. About 2 hours later they called and told me my battery was shot, and that was my problem. The battery just happened to be a Napa battery, and was only about 4 months old, so Napa sent them a new one, which they installed. Total bill was about $64.00. So far so good, but I know there was definite drain on a couple of circuits, so we'll see. I went to walmart and bought a brand new battery to have with me just in case. Something killed the original battery, so we'll see. I'll post future updates.
 
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