Did they replace it with a Dorman or the genuine OEM GM sensor? Because this is a super common failure mode (my '08 LT needs one too) and hear all kinds of horror stories about the Dorman sensors doing just this- failing almost immediately after replacement. I haven’t replaced mine yet because I won;t pay $140 at the dealer and the only one Rockauto carries is the Dorman. For some weird reason GMpartsdirect doesn’t seem to carry them…
Visit the Trailvoy site for more specific info on your trailblazer.