My beloved 2003 TrailBlazer LS came to me after a string of owners - I'm number six! I'm not sure why, but I suspect because of a malfunction, my TrailBlazer has the PassLock system bypassed and I'm trying to program Remote Keyless Entry - which it did not originally come with (no AU0). I replaced the LGM today with a brand new module from ACDelco (https://www.amazon.com/gp/product/B001KSCU7M/?tag=gmtnation-20) and still, my truck refuses to stay in programming mode for more than two seconds. I'm wondering if the PassLock bypass is affecting my efforts or not. Can somebody help shed some light on this subject and assist me in my quest...please? Thank you in advance for any and all advice and admonition, friends.