A pink wire from the "Ign" cavity in the fuse block goes to one side of the switch, and a pink wire from the other side of the switch goes to the coil in the relay; the relay coil grounds through the case tab, where it's screwed to the firewall. When the switch is closed at WOT, that sends 12V to the relay coil, which closes the points in the relay. One side of the points has a tan wire to the fuse block (power), and the other side of the points has a tan wire that goes up to the solenoid in the hood, which is grounded through its attachment to the hood. When the relay points close at WOT, that sends 12V through the tan wire to the solenoid, which energizes it and opens the air valve. If you don't have a good clean ground where the solenoid is attached to the hood, it won't work. The reproduction throttle arm switch is junk - the GM switch works fine.