Turn signal harmonica plug wiring different - 1977

[bigoilman]

In the midst of replacing my turn signal switch and realized that the original has an additional pink/blk and black that the replacement part doesn't have. Looked through my schematics and don't see it there either? What do they operate? Do I need to add them to the new plug? The switch seems to have provisions for them.

Only thing I've found online is for a similar vintage Corvette and those went to the "key alarm" whatever that is. (Edit: found the answer to that, see pic). I guess my truck got that feature (it was a fairly loaded Silverado with Cruise Control) Wires are in positions "E" and "F" on the harmonica connector.

1977 C30 Dually Silverado