I have a 2013. I have had an on and off again battery issue. Most recently I replaced my 14 month old battery after it died. Got the new battery under warranty. One week later, it died! So now I start troubleshooting. I disconnected the negative cable and put my meter to measure the draw. I got 3.20 amps. On the positive terminal there are 4 seperate cables. So my common sense thought I could disconnect one cable at a time until it drops close to zero amps. I eventually had everything disconnected before it read zero. I could touch any of the four cables individually to the positive terminal and it would draw over 3 amps. I even disconnected each fuse box and the alternator.
I am lost.

 

I have a 2013. I have had an on and off again battery issue. Most recently I replaced my 14 month old battery after it died. Got the new battery under warranty. One week later, it died! So now I start troubleshooting. I disconnected the negative cable and put my meter to measure the draw. I got 3.20 amps. On the positive terminal there are 4 seperate cables. So my common sense thought I could disconnect one cable at a time until it drops close to zero amps. I eventually had everything disconnected before it read zero. I could touch any of the four cables individually to the positive terminal and it would draw over 3 amps. I had each fuse box disconnected. Alternator disconnected. I am lost.

 

You need a wiring diagram to chase it further.

 

That is normal for a reading of around 3-4 amps at first.

You'll need to let the truck rest for about 1 hour for a proper current draw.

Basically let things go into sleep mode.

 

Most commonly I would say the alternator is bad. On Ford alternators there is a live wire from the battery to the alternator. It stays live even with the key off. The alternator has what is referred to a final diode that acts like a gate. With the key off, it closes the gate and does not allow current to pass back thru the alternator to ground from the battery. That's a major reason to never buy a rebuilt alternator for a Ford product. Few rebuilders ever check/replace the finals, only check it for output. Might find the large cable on the alternator and remove it. If you see any voltage jumping or sparking, the alternator is bad. It will charge but allows voltage to go back thru the unit when the key is off killing the battery.

 

I had the cable removed from the alternator and it was still showing a draw of 3.2 amps.

 

ManualF150, after an go hour what should the draw be?

 

After time is allowed for the vehicle to go to sleep, pull fuses one at a time until you find one that cuts off the amp draw.