I have checked back 12 pages or more on this forum, searching under key words "battery light", but did not see anything exactly like what I am experiencing with my truck. A couple were similar, but no solid diagnosis and repair found.

The battery light came on in my '04 F150 a couple of days ago. Terminals were in need of cleaning, so I took care of that. The next day after driving 50 miles to and from work, the battery light came on again, along with the ABS & Brake light started flashing. After shutting the truck off, it would not start.

Three days later, I have now installed a brand new alternator and battery, only to have the same symptoms pop up about one minute after start up. The warning lights are now accompanied by the passenger airbag light and all engine instruments needle sweep back and forth. Dash lights go dim and bright intermittently as RPM varies.

Do I need old fault codes cleared or is this a PCM issue?

Thanks to all for your time and look forward to hearing from you.

 

This certainly sounds like a problem with the electrical system, my guesses would have been battery or alternator. Did you have that battery tested before you replaced it? Have you put a multimeter on the battery to see what voltage it's at? It's not unheard of to get a battery that's faulty right from brand new. Since that's the easiest thing to check, I'd start there.

An OBDII code reader might also help shed some light. Some parts stores loan then out for free.

 

Yes, battery was checked and found bad.

But the final resolution on this one is maintainer induced fault. Alternator plug was not fully seated!
Dooh!!!