Depends on the version of Digifant harness. In later years the idle
control gets power from the Fuel Pump relay so it only buzzes when the
ECU activates the FP relay. In the first couple years of 2.1 it was
powered by the ECU power relay and buzzed whenever the key was on. (the
Bentley wiring diagram for 88/89 has serious errors in this area)

Mark

Dennis Haynes wrote:
> Waterboxers don’t have a cold start valve. That buzzing thing in the center of the idle is the idle control valve. It get power when the ignition switch is turned on.
>
> Dennis
>