3588587 and 72 Demon
the switch for the seat unplugs under the seat to replace the switch if it was bad. this would stop the buzzing
the harness is the same for either switch - just uses different terminals when attached.
72 2 speed wiper motors were different from early 2 speeds but none ever came with delayed wipers
the 3 speed/variables speed wiper motors got the upgrade to electric washers and the switch had the push to activate