Hey bro!

It's kinda weird but there are two types of latches on that vintage truck and I'm not really sure the different options that declare which trucks get which....

Long story short, I'd guess you have the type of latch that has the extra switch...and small and fairly fragile slide switch with a small plastic lever the hooks to one of the moving parts on the latch. For a while GM sold the same latch either way and we had to carefully break the switch off (only "glued" from the factory) and reattach it with super glue to the new latch. I do know it was related to the content theft system...then again, GM is so genius using the same light for CTD and VTD.

Although have seen hardly any issues with it I can see how there could be one. Might have broke from age or someone might have slim-jimmed it and broke it. I know you know how to take off the door panel and have a look see...call me if you need more help.