My 2003 Trailblazer LT battery was getting drained overnight, for a week I could not find a solution, even trying the videos on youtube.
I replaced the battery and next day was the same problem, I asked a few people and everybody recommended to replace the alternator, but I remembered my friend had the same issue and replace the battery and alternator and the problem persisted so I did not wanted to follow the same path.
I even considered selling it (which my friend did) but then I decided to replace 2 relays and after that and after almost 2 months the problem is gone.
Check any possible lightbulb in the truck and other fuses too, just in case. I have to take out almost all of the relay and only replace those two because I only have those spare, if you need to replace any other relays, go to your local auto part store it is worthed!!!!
Good luck and don't forget to like my video so I get motivated and post more to make you save money.!!!!!
Thanks
