Hi everyone, I'm new here and my name is Tim, this is my first post and I hope you all can help me.
I have a 2012 Lariat, 6.2L engine. My problem started with the reverse camera not working right, fuzzy lines then all blue, I was getting the message that the reverse sensor system was not working. No problem I had a similar issue with my wife's MKX Lincoln, and figured I needed a new backup camera. So I took off the camera and water came out of the connector and one contact was already corroded and broken off in the connector. I took the old camera from my wife's car and installed it, had to mount it upside down, and it gave me a picture but the parking lines were off and the reverse sensors still gave me an error when I put it in reverse. But I had video which was good enough for now, until I could order a new camera.
2 or 3 days later, I went out to go to work 4AM by the way, it was the coldest it's been all winter so far, about 17 degrees and the truck wouldn't start, so I put it on the charger and took my wife's car. After I got home I checked my 3 year old battery, it was charged but was giving me a CCA of only 590 when it's supposed to be 800, and the tester said for a fully charged battery it was "BAD". So off to buy a new battery and all my problems are over! NOT! The next day after work it turned over once then nothing! Put a battery charger on it and was able to get it started and get home.
So here's what I've found and now I'm stumped and hopefully somebody can guide me as to what to check next:
Amp meter on the battery shows a 4 amp draw after everything shuts down.
Pulling the PCM fuse in the engine compartment fuse # 26, Current goes down to 0.1 or lower amps, putting it back in the amps stay down. But then after the truck is started and shut off it goes back to 4 amps for the remainder of the battery life.
Since this all seemed to start with the backup camera and reverse sensor error, I decided to start with this system, I unplugged the pig tail of the camera, under the truck, to disconnect that cable from the system. Still no change.
I found the reverse sensor fuse, number 34 in the passenger compartment fuse box, and the amp draw goes down to 0.1 and as long as the fuse is out all seems to be working.
I also tried disconnecting the sensor box under the dash near the brake pedal the one that has the speaker on it. That does not make a difference.
So my questions:
Has anybody else seen this problem? and what did you do to fix it?
Is that sensor box under the dash the complete reverse sensor system or is there another module I can try to disconnect?
Fuse 34 says it also is connected to the 4x4, but my 4x4 seems to still be working.
Is there a good place to find a wiring diagram?
Sorry this is so long, but I wanted to detail all I've done so far to keep from going back and forth.
Thanks for any help you all can give me,
Tim

 

If you unplugged that box (PAM) by the brake, that should have covered everything for the sensors, in terms of what could cause a draw. Unless there is a damaged wire under the dash going from the BCM to the PAM, but that seems less likely. That fuse also goes to the camera. You already noted damage on the camera wires, perhaps you didn't fix it all, yet. There is more than one connector that all this runs through right near the spare tire. Probably need to check everything for damage.

 

I damaged three of b/u sensors in my ‘11 power washing mud off the back bumper. They appear to be potted but are not. Each one is plugged into the wire harness behind and above the bumper. Mine simply failed with no excess current draw. You could unplug yours and see if the 4a draw disappears.

Older Ford b/u sensors made an audible click when they worked, ours do not. To diagnose which sensors are bad requires access to the PAM module. The PAM module will give the location of any bad sensors. I purchased an Ancel 700FD OBDII reader to do this. There are other options including Forscan.

Replacement sensors run from cheap to expensive. I read post of cheap Chinese knock offs that worked but the detection range was just a few feet. Went with more than expensive Motorcraft sensors and am very happy I did.

 

Thanks for the info.
I still have a problem with thinking it's with the sensors. I've disconnected the PAM, and still have the current draw. I can understand that the camera may get it's power from somewhere different than the PAM but do the sensors? the only wiring diagram I can find shows they all go thru the PAM.
Plus, the fuse 34 in the passenger compartment shows that it's powered with the ignition on, so why am I getting current draw with the key off but it goes away when I remove this fuse? I do measure about 5 volts on the hot side of this fuse with the truck off which to me is strange.
I understand that it could be a bad wire under the dash, but then it's strange that if that was the case why did it just show up after I messed with the camera? It would be nice to find a wiring diagram, I've searched and so far the only ones I can find are on Ebay for about $65, I'd like to find a downloadable copy for a few buck!

 

This shows the whole line, there are a lot of stops for the camera, the last 3 are all in the back under the bed. It's all the same color wire. Also: ebay

 

Don't forget to put some silicone grease/dielectric grease in the plugs when reassembling it all.

 

Thanks for all the info.
I started in the back and found connector C405, unplugged it and it didn't look bad, no water in it, cleaned up the contacts the best I could, unfortunately I didn't have any dielectric grease, tested it with c405 disconnected and no change, however after I put it back together all is working normal. So I guess maybe I got the contacts clean enough, or just the act of unplugging and plugging it back in did the trick. I tested it just a few minutes ago when I got to work and it's still good, but now I'm scared or paranoid that it will act up again and I'll be with a dead battery some morning! Someone needs to come up with an amp monitoring app that will send you a message if your battery is drawing too much after the shutdown period! Or even as simple as beeping the horn if it's above an amp or 2 after a few minutes!
Thanks again to everybody who helped, hopefully I can pass on some knowledge in the future if someone is having problems I know about.

 

Yup, the unplugging and re-plugging of connectors is really a thing on many vehicles, seems especially in climates such as yours. I highly recommend you get hold of some dielectric or silicone grease (same thing) and fill the plugs regardless, especially any that you've cleaned the pins on, otherwise you can actually end up with micro arcing and further problems.

 

That exists.

It's Bluetooth, so the range is somewhere from 33-100 feet. That could work depending on how close you park.