Hello, I need your help naming the switch with the yellow arrows in the images below. What is it called or what does it do?. This belongs to a 1987 300D with 603 engine. Does anyone know what factory connector this switch goes to? It has a red wire that travels up the a switch next to Y29. I know its not Y30 engine overload protection switchover valve or Y29 Vacuum amplifier switchover valve.

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1987 300D