Ok guys I was useing this from harbor freight and the way I read it was charging inadequately.. ok today I took out my volt meter here is my reading overnight 12.2 startup 14.6 load 14.4 lights radio defroster .. so it seems to me everything is good according to the volt meter .. it is freezing out here in Chicago .. so I think I will buy a back up alternator 2007 with 33k and have it on hand just in case .. thanks

 

If the only reason you have is that sensor, don't worry.

The way the computerized regulator works is different from the "old days". It also takes economy into account, it is not always generating.

However 12.2V is showing an older battery. The alternator will not work with a bad battery, it takes a signal in order to generate.

 

But it's charging. What are you afraid of? Forget that Harbor Freight junk, your volt meter is telling you the real deal. How old is the battery? Cold temps will kill it fast if it has some time on it.
If you really want to load it, turn on everything that's electric. Lights on high beams, defrost (it uses the AC), rear window grid, wipers and interior lights. Then see what your voltage output is at idle and above.
Is the belt original?

 

Don at a 12.2 volt signal to the alternator it will charge. It will excite the field winding thru the internal regulator. You have an output of 14.6, it's working.

 

I was just adding superfluous info, like dead/no battery.

 

My battery read the same 12.2, and it wasn’t strong enough to last another three days.
Cold will kill it.
I replaced the battery did a retest if the charging system and it’s just fine
Original 10 year old Denso OEM alternator 255,000 miles!

 

I knew not to trust that harbor freight sensor that’s why I use a volt meter for sure , I think the battery is 3/4 years old so .. but it starts up on a dime no hesitations at all just don’t want to get stuck in the cold got to say we got the best alternator from the factory mine is pushing 252000 and still going

 

Wholesalegmpartsonline only lists a generator for 2006-2007, GM P/N 10355395. They do not show a generator(or alternator) for 08-11. This is the same GM number for oldblue's first link, 120 amps.

The second link, 130 amps, has a GM P/N 15923218, which I can't really get any GM type site search results.

Oldblue's site doesn't have a generator for the 2.0....