Reverse Lights & Rear Wiper Intermittent

[AtlBenz]

1995 E320 Wagon

Is there a micro switch that activates the reverse lights AND the rear hatch wiper when engaging reverse? more often than not the reverse lights don't activate and when the windshield wiper is on the rear wiper is supposed to activate, and it does not. Every once in a while when I wiggle the shift lever they activate. where is this switch? Fastlane doesn't seem to have it, but then again maybe I was searching the wrong name.