Dash Lights Flicker... Alternator?

[andrewbourdeaux]

Hey guys, my alternator is putting out about 14.1-14.3, but my dash lights, headlights, stereo, etc flicker at idle. When I give it a bit a throttle it levels out. Occasionally the AMP (battery) light flickers on and off, but only at idle. I replaced both batteries about a year ago (x2 big Interstate 1,000-1,200 CCA). Thoughts?

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[Big Bart]

Some thoughts -

It sounds like you have a regulator and or an alternator going out. You likely have the high output altenator being an ambulance. (100 or so amp vs 60-70amp.)

Before condemning one or both of those, check you battery cables and your grounds to make sure they are tight. Also make sure you altenator belt is tight.(I think you have a serpentine belt.) Also look to make sure everything is spinning easily and the belt is not hanging up on a bad a/c pump or something.

But it seems like when your voltage surges and you alt light goes on and off it’s the altenator and or regulator. I always replace the regulator if I replace the altenator.

Maybe start with a new Motorcraft regulator.

 

[TNBrett]

Check all of the wiring between and or connected to the alternator and the regulator. Also check that the screw mounting the regulator is making a good ground connection. Mine did that for a while. I mean exactly like yours is doing. It was odd too, in that some times turning on the head lights, or accelerating would seem to make it stop bouncing the voltmeter needle. I ended up finding a wire that looked like it had been rubbing on something, but wasn’t positioned in a way that that could have happened. Maybe a rodent had gotten to it at some point. Anyway, the wire was corroded and only a couple of strands were intact. I repaired the wire, and have had no issues since.

 

[Slicknik]

@andrewbourdeaux

Check the connecting ends at alternator for good contact , the follow the wiring the other direction to make sure they have good solid contact. Also take the belt off and spin the pulley , how much resistance are you getting ?
My light came on/off rt before my alternator sized at an intersection.

14.1 bolts at idle is fine. Regulator might be failing

 

[franklin2]

Mine was doing that. Like the others said, I wiggled the small connector on the alternator and it would stop. Ended up getting a new connector pigtail.