I have a 2018 F150 XL 4x4 with the 2.7 Eco and 30k miles. When I went out to start it this morning the battery was completely dead. It started and ran fine when I last drove it on Wednesday. I jumped it off my wife's Honda and took it to the local Advance Auto store where the guy tested the battery and said it did not need to be replaced. When I was in the store I noticed that the front parking lights were on. I fiddled with the **** and they eventually went out while I had the driver's door open but when I closed the door they came back on again. I didn't buy a battery and drove home. I shut off the engine and removed the key and everything went off except for the radio. I turned the radio off and waited a couple of minutes and then turned the radio on still with no key in the ignition. Is it supposed to do that? I did that several more times and it still turned on and off without the key. I just came in the house a few minutes ago with the radio and parking lights off so is the problem solved? I know that if I left the parking lights on for 48 hours that would drain the battery down to nothing so could that have been the problem? Any advice would be appreciated....

 

It could be you ignition switch. If you keep a lot of keys attached to the fob, it can wear it out a lot quicker. But, a switch can still wear out with as crappy as a bunch of components are made today. As for the radio, it will work for up 30 minutes with the ignition off. You can change that in the settings on the gauge cluster screen.

Also, the OEM Motorcraft batteries have not had a good track record. They are hit and miss on quality. Back in 2017, my 2 year old stock battery failed to start one day. I took it out and put an new Super Start in. It had been in there ever since, that's 5 years and 3 months now. A new record for me, where I expect a battery to last for 3 years at the most.

 

I have no other keys on the fob. I'm charging the battery overnight so it should be good to go by tomorrow morning. Thank you for your input....

 

If you want to troubleshoot this yourself, get a clamp-on DC ammeter, then clamp it on either the positive or negative battery wire. The amps should be pretty low in the idle state; no more than one or two hundred milliamps.

Then start pulling fuses until the amps drops off. The fuse that makes the difference is pointing to the culprit.

 

How exactly does a clamp-on DC ammeter work? A clamp-on ammeter is essentially a transformer and transformers don't work on DC.
You can, however, disconnect one of the battery cables and put a DC ammeter in series between the battery post and the cable and then read the current draw.

 

https://kaiweets.com/blogs/news/how-...-a-clamp-meter

 

Through the magic of a hall effect sensor.

 

On a 2018, the radio can be turned on by pushing the center of the volume **** with everything else shut off. You get a limited time of function then it is turned off.

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A clamp-on meter detects the electromagnetic field that develops [around a wire] when there is current flow either direction. Both AC and DC work the same.
It is called the Hall effect when measured in this manner.
This year 2018 does not use a HALL effect >sensor< off the battery but uses a Shunt and a different Sensor. than a Hal effect uses..
The negative side of the battery has a series special 'shunt' cable to ground. This special lead cannot just be replaced with just any piece of wire or paralleled with another.
The Battery Monitor Sensor (BMS) measures the voltage drop access this Shunt to ground off the negative battery post.
Normally, the drain after the power system goes into sleep mode, is about 50- 80 ma +/-.
It takes a very good clamp-on meter to read that low a value.
The BMS sensor at the negative post has special internal circuitry to be able to measure the full range and over the cranking limit.
The Sensor delivers all the current ranges, battery temperature, voltage range and charging current to a system module that has the progrsm to control the conditions the AGM Battery type requires . It uses these data points to logic set charge level, voltage levels, time or age of the battery and control the Alternator.
It's not all just the battery and testing, but what the excess drain is when the vehicle is supposed to be at time-out rest.
Is the faulty a Drain?
Is it the Alternator not recharging or the vehicle not driven enough to recover the battery?
Is it the age of the Battery?
Is it a combination of the above?
The capability and knowing about this advanced system becomes a must for trouble-shooting.
Measure and verify the source of the fault then do the repair.
Good luck.

 

Mine battery drain happened twice in 12 months.....I had also tons of issues with the rear door lock a curators, replaced locks twice before ford honored their recall on the lock lock system...they said that wasn't the battery drain, whatever....locks are now fixed and no battery issues for about 18 months...I think the two were related

 

- Many vehicles have higher battery drain than was common in the past.
- Many short trips don't fully charge the battery
- Some problems can be avoided by using a battery maintainer when the vehicle is parked for more than a couple days.
- Any time you think your battery has been drained, no matter what the cause or reason, the best way to charge the battery is with an external smart charger or at minimum overnight with a maintainer.

 

I have had this issue twice with Ford F-150's......both times it was the radio. Replaced radio, fixed.