Sorry to post back on such an old thread; I just wanted to report my results for others who might have this problem. Installation took about 25 minutes and it now works perfectly! I followed instructions in the GM Techline service manual. One tip: buy replacement trim panel clips!!! The old ones end up pretty much unusable. Also, a dedicated trim panel clip remover tool works better than pliers/screwdrivers/etc for getting them out.

Thank you to Scottydoggs, Russosaur, and frosty for responding so quickly and advising me on this issue!

Komrad36