Hi All,

I am new to this forum but all the information I was able to find on it was of a great help to me in the last year.

I now need your help again. I have a 2011 F150 3.5L that has a battery drain issue. After a few days the truck will say that battery is low on start and will says "Start Engine or Turn Ignition Off". Battery is low and really needs to be recharged. After recharge, all is good for a few days. Recharge is done with positive on the battery and negative lead on chassi ground.

I have Send the truck to my Local ford dealer and they have been of a great service but they have been unable to fix this issue even after more than 6 trips to the dealer.

Truck had remote start and key encryption bypass system installed by a third party. I had all of this removed by the ford dealership in hopes of fixing the issue and system is now back to the factory configuration on this. Issue is still present.

Battery has been replaced for a bran new one and tested. Charging system was also tested by the dealer.

I did a few tests and I do see a current leak in the system. It varies from 1.3 to 1.6 A. Total drain is all going to the internal fuse box on the passenger side.





Passenger side fuse box Red wire main input

I am not sure, But i Have isolated the leak by Voltage drop mesurement across the fuses to FU18. If I do remove fuse 18. The current goes down to 0. If I reinsert the fuse. The current goes back up more since the car wakes up. However it then goes down to 0 and no more leak. Car will no longer drain battery at least not enough for my probe to pick it up.

If I stop the problem from happening, I can open the doors and close them the car will go back to sleep no issues. If I play the radio with the key on ACC and get back out (just open and close the door latch fully) the car will go to sleep fully.

As soon as I start the motor and then shut it down. I go out of the car again but then the car doesn't go back to sleep. And will keep draining the battery about 1.5 A until it gets low.

To stop the drain I need to either remove and replace FU18. Of there is a green connector that I can disconnect and connedt it back again. If I do the truck will go to sleep and no longer drain the battery Just like if I pull and put back FU 18.





Green connector, Just under the fuse box on passenger side.


I Have also tried to put the meter on most of the wires and I have only found one that is pulling current. It is a blue with a red line wire connected on connector C1 pin 3 on the fuse box. This cable pull about 0.6A. I do not understand where the rest of the amp is fed.

I am willing to try or to suggest my mechanic at the Ford dealer any leads that you may have. Any help will be really appreciated. Thanks in advance.

Kind Regards,
Charles-Olivier

 

Ok,I found fuse 18 in this link, on page 10.

http://www.revbase.com/BBBMotor/Wd/D...dPdf?id=878538

Looks like it works the brake interlock for the shifter/floor shifter, PCM, and a couple things for the factory keyless entry. I wonder if that green connector you unplugged has one of these circuits in it.

You are doing very well I think troubleshooting this. With this little bit more info and wire colors/circuit descriptions, will this help you continue? The problem is it's hard to troubleshoot this without damaging the harness in the process by cutting wires.

I am not sure why they have to "wake up" the PCM for the engine. In the old days the keyswitch "woke up" the PCM so it could run the engine.

 

Are you waiting the required 40 minutes after touching anything to make your measurements? Failure to allow the battery saver circuit to engage is a common mistake in attempting to diagnose battery drain concerns, just want to ensure it is not being made in this case.

 

According to the owner's manual, fuse 18 feeds the Brake-shift interlock, Keypad
illumination, PCM wakeup, and the PATS. So it's possible the brake-shift solenoid is constantly engaged or the keypad illumination is always on.

 

Speaking of a brake solenoid, I have run into solenoid failures on many different pieces of equipment. The last one I worked on was a lever interlock for the hydraulics on a skid steer. The mechanical pin on the solenoid bent, the solenoid then could not pull the core into the solenoid. When that happens it overheats and burns out the windings in the solenoid, causing a short circuit. In this case it was dead blowing fuses out on a construction site.

Like I said I have seen this many times before. If the guts of the solenoid cannot make their way up in the windings when they are energized, it burns the windings up everytime.

 

Hi again All,

Thanks a lot for all of your replies. Your help is really appreciated. Here is the answers I can give you.

projectSHO89
No I do not always wait the whole 40 minutes interval. I have been trying to troubleshoot this for a While now and When I her the relay cick. Around 5 minutes after I know that it will not go down lower than that. I have just testes again tonight. I have waited 40 minutes, then 1 hour and even after 5 hours I still have the same current drawn. Thanks for pointing this out You are right to recommend this. Regards.

Franklin
Thanks for the drawings I have found those. I am however unable to find the wire that has the leak on he connector. I also Cant find how to identify what is the connector number of the green connector I have mentioned. Would you have another resources to help me find this information. Once again thank you.

Alloro,
Thanks for the answer. I know I have some issues with the Keypad. I can't unlock the doors with it anymore. It will however not stay lit up. I have also tested lignthing it up on all the buttons and one seems to be not working. But the button is not in the sequence for the factory code. So this is somekind of hard to understand. I have tested by disconnecting the keypad inside the door and the problem was still present. Would you recommend I keep it disconnected.

Regarding the floor console. I have it oppened and I mesured if I have any current on any of the wires I could see. I read no current with my probe at all. Would this eliminate this from being the problem? I have also checked to see if the car sees it is in park. All I know is that the dash is not illuminated after i remove the keys ans closes the doors and and the car seems to be sleeping if not for the constant current draw.





Oppened floor Console Shifter.


Would any of you have any more ideas. Any help is really appreciated. I will also try a second time all you would recommend as any test I do might not always be perfect.

And Here is the truck you will probably understand Why I want to have it fixed.





Kind regards,
My Truck Next to 3 Vipers this afternoon.

 

You can't find those specific colored wires that are shown in the diagram in that green plug?

blue/orange

violet/orange

white/green

 

I am not even going to hazard a guess here. I would say you are doing darn good work; better than the Ford techs it appears!

Shall be interested in the resolution, so do let us know WHEN you do find the cause of the problem.

 

Sounds familiar, I have a 13 F150 Limited battery drain problem as well, has been at dealer for 6 weeks, minus a total of 2 1/2 days when they said it was fixed, NOT, still bad. They have changed the light sensor on the dash, the key switch, the entry key pad, the battery, I had 2 changed within a month right before taking to ford, the instrument cluster and last the bcm, what I have found is the truck will turn on only the dash lights after approx 10-12 minutes. Not the dome lights or radio. I do normally back my truck up and then shutoff. Don't know if that is a factor. Ford did tell me the draw on my truck is circuit 18! I will let you know if they ever figure it out, I doubt they do, I am a marine mechanic and would not take it back but for warranty paying. I am trying to figure out a pattern for the light display coming on, also the seat memory and steering wheel is lost about twice a day,

 

Hello
I was reading this thread an the 1.6 AMP draw is exactly what I am getting on my 2011 F150 lariat with the 3.5l ecoboost motor. The power draw is intermittent and when my clamp is getting the 1.6 amp draw it will last exactly 30 seconds every time. After about 5 minutes it will happen again until the battery is depleted in about 4 days it won’t start. I know the issue is coming from the inside fuse box/ BCM. I think the problem is coming from the body control module. Has anyone been able to fix an issue like this? I’m about ready to buy a new BCM the problem is programming the unit. Any input would be greatly appreciated.
Thanks Dave

 

been trying to trace this problem for awhile and nothing. by chance did you ever figure it out?

 

"larcho" last visited this site in 2017. Unlikely to get a response from him.