F150 batterie killer



After replacing 10 yr old Motocraft batterie,Am encountering electric probs.4WD light flashing on/off and clicking wlile not in use,Warning alarms going off for no reason(everything shut off,) Everything!,Keys in hand, Doors closed.Bells ringing inside vehicle.And my windows do not function whilst this is happening.Batterie is being killed ,But I can easily charge/jump after no life at all. No lights no nothing, Brand new Batterie. Could ya shine some light please


Try a ‘hard reboot’ of the body control module. Disconnect the battery overnight and reconnect in the morning. See if that helps.


I believe that your alternator is in its last death throes.
When an alternator begins to fail, the voltage spikes produce all kinds of weird reactions in the car’s electrical/electronic systems. Trust me–I have observed much electrical weirdness as an alternator is failing.

Interestingly, it is possible that the 10 year old battery was the cause of the alternator’s problems. When an alternator has to work overtime to try to keep an old battery charged, it is very possible to kill the altenator in the process. Trying to economize by getting that extra year or two out of a battery can frequently result in spending a whole heap more money when you have to replace the alternator as a result!

Anyway–I would suggest that you have your alternator’s output checked today, before you wind up being stranded in the cold.


thanx,Will try hard reboot


outstand Batterie life dontcha think? Thanx I will deffinatly have alt tested Merry Christmas to all


Will the OBD provide any info on the problem?


If ya mean service lite ,No ,Have hard rebooted and have tested alt . still having prob.The batterie is up, and when I touch the key in ignition I lose everything ,All lights, bells KAPUTT!! Starter??? is only cpl yrs old , Switch??? Still a dilemma


What do you mean when you “touch the key in the ignition”. Do you mean when you turn the key to start or just to run, or kust put the key in?


I only am turning the key,Just at the first click in switch everything goes .Inside dome light goes off bells stop ringing etc


I wonder if they ignition switch could be out?


I have to think there is something wrong with the ignition switch also.


I found negative terminal at batterie loose .Didnt need a jump. However, after starting truck,I put in 4WDrive. But it kept flashing on off (4WD light) on off finaly I lost 4WD and got stuck. This morning truck started fine and I again have 4WDrive.The flashing 4wd light has been flashing ever since I changed batteries. Coincidence? 4Wd relay?


Perhaps the flashing light means there is something wrong with the 4WD system. Check the Owner’s Manual to see if it says anything about the flashing light.


owners manual says if 4WD indicator lights flashing in 2WD to contact Ford authorized dealer.I guess thats where im headed. ASAP Thanx for imput Willy