I have a vacuum switch mounted slightly to the passenger side of center of the firewall on my 84 245GL. The tube goes to the right connection on the throttle body. It has a blue and yellow wire coming out of it and the blue goes to ground, nothing on the yellow, not even a connector, just hanging in the wind as if it were cut. Anyone know what this is supposed to do? The switch makes continuity to ground on mild acceleration. The car seems to run ok but not sure if it could be better because I'm new to Brick driving.