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Your speedometer acting up makes wonder if the module that drives it is failing which might drain the battery. My ‘11 FX4 was under a recall concerning the trans shifting into 1st gear while cruising highway speeds. The fix was a new vehicle speed sensor. Just a shot in the dark.....
 
Your speedometer acting up makes wonder if the module that drives it is failing which might drain the battery. My ‘11 FX4 was under a recall concerning the trans shifting into 1st gear while cruising highway speeds. The fix was a new vehicle speed sensor. Just a shot in the dark.....
Some just needed a flash and some needed the leadframe replaced. Is the speed sensor part of the tranny leadframe ?
 
Try and disconnect you altanator wires at the altanator and check again be careful one of the wires may have power to it. You need to find a wire stymatic to help trace this down there are some circuits that are hot all the time you need to find those and try to disconnect.
 
The only thing I have seen on the forums is the switch for gear seletor going bad, keeping them lit up 24hr till you replace or like gear head above said, I have seen a few people find out it was related to some part in the 110v "home style" plug.

By chance, do you have any 3rd party devices plugged in? tuner, radar etc? Or any kind of cable(usb etc) plugged in anywhere?

Have you tested the battery it self? Might be bad too.
 
Discussion starter · #28 ·
No USB, 12 V or 120V connector has anything plugged in. The battery is fairly new and will accept and hold a charge if you disconnect the ground. The alternator puts out 14.6 volts when idling.
 
Try and disconnect you altanator wires at the altanator and check again be careful one of the wires may have power to it. You need to find a wire stymatic to help trace this down there are some circuits that are hot all the time you need to find those and try to disconnect.
+1 on this. Does your alternator feel warm to the touch well after the engine has cooled down? Even though the alternator is working and charging properly when running, it could have an issue causing it to start the draw. Just a thought since it seems you've covered everything else.

Also it doesn't look like it based on your positive terminal, but do you have any aftermarket lights or anything that have in-line fuses not located in the fuse box?
 
Discussion starter · #30 ·
One other thought here. On occasion when I put the key in the ignition and turn it, there is a lag between the turn of the key to the start position and the starter motor actually operating. It is very slight but if you pay attention you would notice it. Wondering if that may be contributing to the issue. Still not sure why it would not show up in the fuses, but wondering what the group thinks.

Also there was a question about the battery, and I guess i would say that I believe it is fine because if I disconnect it while it sits overnight, there are no problems starting the next morning. I can leave it connected if I am running errands during the day and it still has enough to start the truck.
 
I mentioned this early on but the truth is I have no idea. I still have to wonder if you‘ve got a bad set of diodes in your alternator. Should be a set of 6, sometimes just a pair go bad and the alternator still “sort of” works.
 
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