Hello members. So my battery light has began to flicker. Doesn't flicker from a dead stop but mostly when I'm already at cruising speed and begin to accelerate such as a hill or incline in the road. I replaced the alternator and had the batteries check. Belt is tight and tensioner appears to be proper. Batteries check out good. Only thing abnormal is when the tech has his machine hooked up to the drivers side battery, it says alternator not charging. However, when he connects to the passenger battery, its says alternator is charging. I disconnected batteries one at a time and the truck cranks fine on either battery. I've checked and cleaned all connections and the flicker still continues.

 

Sorry, 2006 F250 6.0 if this matters.

 

There is a good possibility a poor connection exists within the charging system. A good tech should be able to find the problem and correct it.

 

+1 for the above.

Things you can do:
1. Make sure the battery connections are all good and tight with no corrosion.
2. Check the battery grounds. The main one is at the bottom of the engine block on the passenger side. It is usually the one that is most corroded. Both batteries then have a ground to the frame, and they are somewhat of a pain to get to.
3. Make sure the sensing wire connector from the Instrument cluster is firmly connected to the alternator, and that the wire is in good shape.

Ultimately it is possible that it is an instrument cluster issue.