2006 GMC 3500 flickering dash and headlights

[skyking]

My instinct is to replace the alternator and give that a try, but I am loathe to toss parts at something. it charges the batteries OK, I put a digital voltmeter on it and they do not track fast enough to show this flicker, but the voltage tracks along as expected. No I don't have an oscilloscope.
If I toss a $200 alternator at it and the problem does not go away, it is not the end of the world. I m hoping somebody has seen this issue and can lend some insight.

 

[herm0016]

voltage regulator, sometimes loose connector on the alternator or the grounds.

regulator can be replaced though it is in the alternator for around 20 bucks

which engine? 6.0, 8.1 or dmax?

$75 to $250 on rock auto for a whole unit. I would go with ac delco.

very similar to my 2500 8.1L suburban.

 

[skyking]

It's the 6.6 duramax. $200 for a reman at Autozone.

 

[RLGL]

You are willing to throw $200. at the thing, why not spending some time troubleshooting the system first?

 

[96Firebird]

Since you have a DMM, checking grounds would be the first and easiest thing.

Places like AutoZone claim they can test alternators in the vehicle, not sure what they do but might be worth a shot.

 

[Pontius Dilate]

Start with the headlight switch, since it turns on power to dash lights and headlights? Looks like it's really easy to get to on that truck.

 

[skyking]

You are willing to throw $200. at the thing, why not spending some time troubleshooting the system first?

I'm all ears.
When I say intermittent, I mean it does not happen all the time. When it does, it is a very regular pulsing that only happens with the engine running. You can see why I suspect the alternator itself.