Switch on the intake manifold

[WMO Madness]

I am in the process of clean extra parts for my 1984 300D to Hydro print them in Red Carbon Fiber pattern. When I removed the intake manifold from another car, it had thick junk inside I guess it is from the oil being sucked in from the cleaner. Anyway, there is a switch attached to the monifold, the hole on it was clogged from carbon build up. What is the switch for? I took a scribe and clean it out and sprayed brake cleaner to remove the junk, now it is clean. Thank you.