Service Charging System
 

I have a 2000 STS, Northstar motor.
The service charging system message light and battery light came on.
later driving home, the battery saver turned a few things off.
the dash info shows 11.2 volt, I checked the battery with a load and says weak but not bad. I removed the neg. side of the battery, all looked great, tightened both Pos. and Neg. post.
Firestone with out checking anything said it s the alternator, $800.

Looked under the hood. Cant even find the alternator

Just Not sure what to do..

In Advance.. Thanks

Many parts stores will test charging system for free. Alternator is replaced from under car, and PITA to replace. GM Service Plus dealer would replace it with Lifetime parts and Labor warranty. When getting estimate get part, labor,& warranty when you just get a total you may not get the best deal If you plan on keeping car for several years Lifetime P&L or If DIY lifetime part is the way to go. It like a 7.5 on difficulty scale.

Anyone know where the negative side of the battery connects to the engine area.
Its good at the battery but I wanted to check/clean at the motor

There really isn't a ground cable. The ground plane is the body and the related components that attach powertrain. There are ground buss bars on frame rail and transmission under water pump. There should be codes set in pcm and dim.