Alternator wiring
99 00 Silverado GMT 800 PCM only uses 1 wire on terminal L.
01 02 Silverado GMT 800 PCM use 2 wires terminal L and F.
Found these gif's of the wiring elsewhere on the site.
If you have your own tuning software you can look under the systems tab for the OS you are using and change these settings as well.
HTH!










