2011 F150 Super Cab - been having a problem with my battery draining every night so that I need to jump it in the morning to start it, and noone can seem to figure out what the problem is and I'm wondering if anyone else has had this issue? It started back in October after I had gone on a trip and parked the truck in a garage for 2 days. Called AAA and the charging system tested OK but they said the battery was shot, so they replaced it right there (actually a good deal and easier than schlepping to AutoZone or wherever, bringing back to get core charge returned, etc). A few days later it wouldn't start in the morning, so I jumped it and brought to my local mechanic (who is excellent and owns an F150 himself). He tested every circuit and couldn't find the problem and reluctantly said I should bring to the Ford dealer in case they need to reload the software or whatever. Brought it to Ford and they claimed it was the FDIM display that was draining the battery, and the best thing was just to unplug it since a new one was $800, but on backorder. So I left it unplugged and searched for a used one, which I found for $85 and ordered. Of course, before I received it the battery died again, so I suspected I actually had a faulty battery and had AAA replace it for me (they pushed back a bit, but not too much). I put in the used FDIM and thought I was OK, but of course it happened again and back to the dealer for the 3rd time. Yesterday they told me it's dying every night on them as well, but they can't seem to figure out what the problem is. They've had the truck for nearly a week, so I'm not a happy camper and would think they could contact Detroit and get some guidance on what to do, no? Thanks for any advice/counsel you can provide, since as you can probably tell I'm a bit frustrate with this!

 

Does the P light up when you are in Park? (truck on)
Does anything happen (stuff turning on/off that shouldn't) if you just put the key in the ignition and wiggle it? (truck off)

 

It's still at the dealer, so I'll check these things when I get it back tomorrow. I truly haven't see any lights/displays that are out of the ordinary, but appreciate your reply and will give these a try.

 

I’m not a professional car mechanic, but I am an electrician.

I would put a DC amp meter in series with the negative battery cable.

It has got to be pulling parasitic amperage. Start pulling one fuse at a time till amps drop off, that’s the circuit with the problem.

 

To the OP, i agree with both of these comments. The beginning of this video explains what Spiky is referring too.

Heres a link to the switch that needs to be replaced if in fact this is your issue.
https://www.ebay.com/itm/2011-2014-F...kAAOSwo4pYg-KO

If that isnt your issue then get a DC Amp Meter and perform a Parasitic Draw Test like Lee308 suggested.

Heres a link to show you how to do it.
https://www.ebay.com/itm/2011-2014-F...kAAOSwo4pYg-KO

Wayne

 

Thanks so much, Wayne, but I don't see the video. Can you please resend? Thanks again - much appreciated.

 

Both your links go to the same page.
I believe you intended the second link to point somewhere else.

 

Sorry Fellas, I didnt realize i linked the same thing twice.

Heres the correct link.


Wayne

 

Usually when someone brings a vehicle to me with a really strong short circuit that draws the battery down overnight, and all of the circuits test good, that's when I start looking at the alternator.

See this fairly regular - the internal diode shorts to ground, but the alternator will still charge. Draws the battery down overnight every time.

Disconnect the big main cable to the alternator and see if the short goes away. If it does, then use your meter to measure the ohms between the alternator post and the alternator case. You should have continuity in one direction and if you switch leads you’ll have no continuity. This will tell you the diodes are good or shorted. If you have continuity in both directions then the large post is grounded or the internal diodes are bad.

Tim

 

So I just watched the video.
The guy is really good; and knows his electronics.
And that's exactly how I would troubleshoot a parasitic amp draw.

What I can't figure out.... is why in the heck that car has a dash switch for allowing the radio/lights to be on constantly.
I have never seen that before.