I have a 2004 f-150 which is having battery charging problems. I have a older blue point charging tester and the fault light for field regulator open is on.Any ideas as to what this means and how to fix it. I had the battery tested today, it was fine if that helps.

 

Not 100% sure on your MY, but the 97+ MY had a fuse for the alternator field. Did you check if you had one, and if it was good ?

 

I don't have the owners manual so I don't know if there is a fuse or which one it is. Any help would be greatly appreciated.

 

I don't know about the fuse, but you can get a free copy of your owner's manual here: https://www.fleet.ford.com/maintenan...ls/default.asp

- Jack

 

I answered for the truck in your profile, not in the post, sorry.

Your 2004, it is a new body style or 2004 Heritage or Lightning ?

 

I'm sorry for the confusion sscully. It's the new body style 5.4 v8 lariat. Not the heritage or lightening model. Thank you for your time.

 

No problem, my reading comprehension this AM was not working so well.

In the case of the 04-08 MY charging system, there is not a fuse for the alternator fuse, the charge is directly controlled by the PCM



I would think at this point having the alternator tested is in order. Thing is the test needs to take into account for the PCM controlled charging circuit.

 

I'll take the alternator in for testing later. I was hoping for something simple but maybe a new one is in order. Thanks for your time.

 

This is just my thought on the topic, don't know if jbrew or JMC have another thought on the topic ( or anyone else ).

 

I took the alternator to autozone for testing and it was shot. New one is fitted and running like a swiss watch. The regulator and rectifier are built in on these so i could not just replace them. I was surprised how easy it was to change. Thanks to sscully and jackandjanet for all the advice. I hope to be able to payback the favor one day.