Hello,
I'm jus joining up with the community but have been reading alot. I just bought a 2000 GLS 2.0l and have been making a few mods. i had a new stereo installed yesterday and now i seem to be having alternator issues. the charge light is constantly on and when i tested it then got it tested at Autozone & Advacned Auto the conclusion is the same overall output is 11.48v. A far cry below the norm of 13.2-15v.
Basically i'm trying to see if anyone has had this issue after installing an aftermarket radio. i am in the process of double checking the wiring on the install to see if there are any shorts. Any help would be appreciated.

CHecked and double checked the wiring of the audio system power installed and nothing is out of place. called up ma buddy (the previous owner) and he had no issues with the alternator. guess athena's(my jetta) due for a new alternator is all. any links for decent prices for quality parts?

Open the hood and open the fuse box on the battery. Check the large black wire. Any melting? If so, replace the alternator harness AND fuse box. VERY common.