I have a 2010 Ford F150 Lariat. I've been experiencing a parasitic drain on my (new) battery. Today I ran a series current test from the negative terminal on the battery; was seeing a constant (not intermittent) draw of 400-500 mA. I started pulling fuses and when I got to fuse #64 (in the front of engine fuse j-box) [see https://www.startmycar.com/us/ford/f...anchorfusebox0] I saw the quiescent current draw stabilize down to 10mA (my rig was fully asleep for over an hour). With f#64 out, I charged the battery back up and when I finished charging, I disconnected and watched for significant voltage draw-down like I was seeing before, and it appears to have worked. So assuming I reconciled the issue of battery drain, now I have to determine the cause.

My Audio DSP is located under the center console, my audio control module is located under the center of the dash, and my subwoofer amplifier is located at the base of the right C pillar (rear right seat). In terms of testing, what components in this system should I target, and what is the protocol for the testing. I have my meters and good familiarity with DC V & I. I know where my groundings are located if anyone thinks they'd worth inspecting/cleaning.
Also I have the electrical diagrams for the whole rig (am happy to share pics if you need them).

Thanks!

 

An accurate diagram is usually very helpful.

Before making you go thru a lot of trouble, are there any other gadgets, add ons, presently connected to the vehicle?

They can cause all sorts of problems.

 

I'm happy to say it's all stock; the only aftermarket tinker that found was some wiring to a light bar for the canopy (I've since removed all traces of that electrical installation).

Below is a link to 3 subsets of diagrams:

• 3 pages for the 'Navigation System Wiring' (these show Fuse #64 present in the circuit; this is the fuse I pulled to stop the drain - I no longer have any sound from my speaker system)
• 3 pages for the 'Premium Radio Wiring' (these also show Fuse #64 present in the circuit)
• 1 page for the 'Base Radio' (Fuse #64 is not present, but I thought it might be relevant)

Here is the link to my Drive where the pictures are stored (let me know if you have trouble accessing them) > https://drive.google.com/drive/folde...usp=drive_link

 

Please keep in mind your vehicle's radio is one of the modules in the vehicle's network and if it is not, or cannot function , communication on the network is hampered.

All sorts of weird things happen when network communication is lost..

 

Copy that; turns out the issue was not the circuit on Fuse#64 - woke up to another drained battery the other day. I think the current draw that I observed when testing was a result of me waking the system up, thus showing general current flow from reenergizing the amplifier (a "false positive" if you will).

In the time since I bought the truck there have been a few electrical blips that have drawn my attention (rear power window, cigar lighter, power seat, sunroof, and backup camera). I've taken that caveman approach and removed the fuses from those suspected circuits, stripping down the accessories functionality to bare bones. My goal is to see if the parasitic draw stops with these circuits interrupted; if so, then I can assume the issue is with one of these circuits.

Would an computer scanner help me pin point the specific cause?

 

I believe a good scan tool will only show anything if,,,,,,,,,one of the systems it monitors shows a possible problem or malfunction.
You are hot on the trail, but I believe a better way to help pin down the cause would be to do voltage drop testing over the fuses.
As you know the removing and reinstalling a fuse will allow some circuits to reset and the results could be inaccurate.

Some folks have even used thermal measurement to help pin down a fuse carrying current.

Are you checking fuse panels in the engine compartment AND in the dash panel ?

 

Yep, I've checked the blade fuses via voltage drop testing, and haven't detected anything, but unfortunately about 30% of the fuses are the cartridge style which don't have the contact points for the meter probes, so I'm not able to drop test those ones. I would actually like to try the thermal/infrared test if I can find an affordable tool, but I'll try to computer scanner first and see how that goes.
And yes I'm checking both fuse boxes, one in the engine and one by the passenger kick panel. I put a new battery in last week and so far, with the handful of accessory fuses removed (non-active circuits of non-essential features), everything seems to be doing great. I think the previous battery might have had its assed kicked from getting drawn down so many times. So with a fresh battery, I'll run the scanner and start testing the circuits that are still active, then I'll gradually begin re-energizing the circuits for the fuses I removed.

 

There is a possibility for a problem to be missed and that is when fuses are pulled and reinstalled , even at a later time,, this allows the system to reset and the drain not now appear..