2006 Impala SS

My impala has recently sent a p0621 code. Generator lamp L circuit malfunction.

The AC compressor seized about a month ago and I replaced it. I had to remove the alternator to get the belt back on but the alternator is currently charging the battery normally. Any ideas as to what the issue could be? I need to get it inspected and I assume it won’t pass even though the code has nothing to do with emissions.

Take a look here:

Since the AC compressor swap and error code SEEM related, I’d be checking the wiring on the alternator carefully to see if you’ve damaged a wire when the compressor was changed. Other causes are in the article.