I just put a new battery and starter. Battery voltage is good. With truck running the alternator is charging the battery good with everything on. All my wires are nice and tight. Not sure what is going on here.
I had replaced the small clip going to the alternator because I originally thought that was the cause of the blinking. I got a junkyard wire and soldered it on and there was no light for a week or so but now its ramdomly going on and off all day. Even with the battery light on the alternator is fully charging the battery , it was like 14.5 volts or something.
Anyway I can test the actual wires going to the alternator?

 

How old is the Alternator? Is it a Motorcraft?

 

I assume its original alternator with 182K miles.
But I would think if it was bad or a loose wire I would not be getting the correct charging voltage at the battery.

 

Alt with 128K on it, time for a new or rebuilt Motorcraft, IMO. When my wifes 04 Expedition would randomly blink, on acceleration, dealer replaced alt.

 

Sounds like brushes or a loose connection to me. Do your headlights flicker? Dead giveaway for bad brushes.

I did a write-up on how to do it on a Ranger/Explorer years ago (they are also 3G alternators - but a different configuration). Hope this helps.

http://www.therangerstation.com/foru...ad.php?t=94951

 

Everything seems normal except the fact the light keeps going on and off.

Is there a proper way to test the wires going into the alternator with a electrical tester? If I put one lead on negative and the other inside the wire should I get the same reading as from the battery?
Or is there a way to test the voltage regulator?
I learned from the last time to not just go replacing random parts hoping it works lol

 

Ran into a blinking battery light on a 2005 ford escape after replacing the alternator, the battery & alternator voltages was good.
I pushed the wires in (what I call the D plug due to its shape) towards the alternator at the harness D-plug & the light went out.

I had got the idea to check it on the Escape after reading (from a Google search) that people with f150s (I dont recall the year models) would have there light come & go when driving down rough (dirt) roads & found it was the same plug connection issue.


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My 98 would do the same thing, intermittent, it would blink, stay on for a bit , then off. Couldn't find anything wrong in the system for awhile. Finally the light stayed on. Went under the hood again, moved the allt harness around and heard a sizzle or arching sound coming from inline fuse holder. I've already checked the fuse/harness previously. Well because the problem was intermittent, it tested good the first time around. What was happening, one leg of the fuse kept dislodging inside the holder, - hence the arching sound. The fuse connection shorting, every time it did the battery light would blink. Finally replaced the holder as the fuse would pop out on it's own inside the holder.

 

I forget what year your truck is.... but if everything else seems normal, I'd look into Brew's suggestion. 97 and 98 had this issue especially.

 

If his signature is correct, its a 17 year old truck.