Harmonic Balancer or Crankshaft?

[DakotaGrey]

I have a 2010 buick lucerne CXL with the 3.9L motor, and I believe my harmonic balancer went out, but I'm not 100% sure so I'm just trying to get some thoughts before I take it anywhere.

Now I'm no mechanic so if I say some things wrong, sorry!! I mean I've done some basic TLC things like, oil change, alternator replacement, spark plugs, etc, but I'm not sure about any pulleys, so I want to know how hard is replacing a harmonic balancer if it's that

Anyways, I was driving and noticed the battery light came on and I lost power to the car, so I was able to pull over and I opened the hood to notice it smoking a little and I noticed the harmonic balancer was spinning but looked like the rubber seal on it had worn away and it would also seize at times so I quickly shut the motor off and had it towed back to the house, my question is how can you tell if it's the harmonic balancer/crankshaft pulley or the whole crankshaft? And again is it hard to replace if it's just the harmonic balancer?
Thank You for any feedback!

 

[DrivenDaily]

If you are able to see the outer pulley of the HB slow or stop spinning at any time that the center continues to spin, then it's toast.

A buddy with a 1999 Mercury 4.6L had his doing that, but mostly only when the PS or AC put it under a load.

What I did to confirm was put marks on both halves of the pulley (inner and outer) across where the rubber is. Then I started the engine, turned on the AC, listened for that special squeal sound, then turned it off. The marks had moved! I replaced it for him and it drives so sweet now!