nufan

04 FX4 Supercrew 97,700k.

Parked truck Wednesday night. Thursday morning wouldn't start; turned over once, gauges were twitching. Outside temp was about 38F. Came home from work about 4:30 and truck started but gauges didn't move for about 1 sec after truck started.
Brought to Auto Zone for Battery and alternator check. Battery showed 89% charged and 98% health.
Alternator read 12v off load and 15.59v on load.

Started Friday. Changed oil on Sunday, truck started, but was no smooth (gauges did not move for about 2 sec after truck was running).
Monday morning (42F), leaving for work, truck dead. No turn over, no keyless entry, head lights very dim.


Thoughts?

Thank you.

vintageman

Sounds like alternator to me. I have never seen a good alternator put 15.59v on load, normally a good one is around 14.8 or so.

jordanb8812

You might take off the battery terminals and check them for corrosion.

Mod (Ret.)

With the truck being a 2004, I'd assume you are on your third battery, and if we use tha average of 4 years to a battery life, the third one is into its third year.

Is the battery in there now a decent name brand? It sounds to me like it may have a bad cell. The alternator output is a bit high; it should be around 14.8, so it may be overcharging your battery, basically cooking it.

Ratsan_Fratsan

I have to agree, sounds like a double problem. You have an alternator that's putting out to much and the Bat. sounds internally intermittent.

Both of these issues can easily lead to other electrical problems if they haven't already and should be fixed ASAP. I would change both at the same time and leave the bat. unhooked for a good hour or more before installing it. Let everything reset. Make sure all the connections are clean as well.

Dsherman

I would replace the battery first with a new one as the condition of the battery will effect what the alternator does. But I agree that the alternator shouldn't output the 15.XX volts. Seems like the battery is trying to suck the insides out of the alternator.

Modular man

Change battery first

nufan

Sent it off to the ford dealer to check it over. All they said was dead cell in battery and 2 spark plugs were loose (the back two) I replaced them in July.

Got a new battery; thank you warranty!

Came home and checked the plugs, don't see how they were loose, I could barely break them free, but the boots did have a rust colored power on them and smelt of exhaust.

homer

You should be 13.5-14.5 volts... if you're higher, you might be overcharging your batteries. It may be a voltage regulator issue. That's definitely far too high at 15.5+. If a voltmeter is reading higher than 14.5 at the terminals while running that's not right at all.

Mod (Ret.)

I'll have to assume that Ford checked the output of the alternator when they gave you a new battery under warranty.

However, if this battery fails early, then I'd be weary of your alternator, especially if it's putting out over 15 volts, as this will overcharge a battery, causing it to fail early.