and do NOT use the + side of the coil !!! The voltage at the coil runs through resistance wiring...so you need to find 12 volts somewhere else. In later models, there is a 12V source in the harness right near the brake master. If the car has A/C, there is a tap there for full 12volts to power the carburetor solenoid. It's a 3 or 4 contact plug...should be somewhere between the back of the drivers side valve cover...near the brake master/booster.