mk1 throttle body, now sorted

Hi another tech question. on my 1.8 gti, 89 cab. on the bottom of the throttle body is a micro switch, connected by a plug on the front of the body. should this be touching the throttle arm,? its not on mine. and what is it ????
Me again, its the air bypass switch, cleaned out my throttle body and reset it all, she sweet now, runs much better