battery symbol came up on my 2010 fx4 , so I tested the battery by itself and had 12.8 volts
hooked battery cables back on, started truck and had between 14.1 and 14.4 volts running
was going to the shop for inspection so had them check it out, mechanic told me it was a bad alternator, needed to make an appointment
just replaced alternator myself, still had 12.8 volts on battery,started truck and have 14.3-14.4 volts running but the battery light came back on

what else to look for?

 

Don't forget to follow the instructions in the owner's manual regarding changing and/or the battery and the need to rest the BMS (Battery Management System).*NOTE: FoMoCo dealership service can reset the BMS using their IDS (Intergrated Diagnostic System) negating the eight hours of vehicle sleep time requirement.

(owner's manual) Don't have one -OR- would like a digital, searchable desktop document?.

 

I had the issue with the battery light on my 2013. Took it to the dealer because it was under warranty at the time. They found a loose positive battery cable. Light has not come on since.

 

 

did the BMS deal, no luck
and I put a brand new over-priced fomoco alternator on it so reading the post I need a crappy 3rd world reman motorcraft unit?
wont use ANYTHING motorcraft, no worth the price of packaging
never used any of it in the other 2 dozen ford products I have owned and never will

yes, i know motorcraft is ford, but it still dont cut the mustard, if Im spending money its on new parts


BTW, light still on, thinking I need to have battery load tested as even a battery with 1 dead cell will still put out 12.7-12.9 volts

 

Don't know if it's related, but I had the same issue. Then my truck broke down due to the melted fuse for the fuel pump issue. I had that fuse relocated with the fix kit at the dealer. The tech thought that the battery light issue and the fuse melting might have been related. It has not come on since, but I haven't driven my truck for extended periods of time.

 

Do you have this sensor on a 2010?
https://www.f150forum.com/f38/disabl...4/#post3603457

 

 

I will have to get some time and look for this, thanks

there are still places where you can buy brand new alternators, you have to seek the sellers out, usually the automotive electric shops that seem to never have any business sell the things
there is 1 such shop here in upstate ny,

and its the 5.4 motor, does that help with anything?

 

My bad, mis'. Missed the fact that the OP had a 2010. DOH!

BMS (Battery Management System) wasn't introduced until 2011.
.