Throttle Switch (4.9L)

On 4.9L using an Idle Speed Control (ISC) motor, an idle switch is incorporated into ISC motor. This switch informs ECM when throttle lever is contacting ISC plunger. This allows ECM to determine when to control idle speed. When throttle is open sufficiently to relieve pressure from the ISC plunger, switch will open and ECM will no longer attempt to control idle speed.