Shift Light: Description and Operation

The shift indicator light, which is located in the instrument panel on manual transaxle models, is used to urge the driver to upshift at the proper moment. The shift indicator light activates as soon as vehicle conditions become suitable for operation in the next higher gear, then de-activates as the clutch is released for upshift.
The engine parameters used to activate the shift indicator light are engine speed, engine load and coolant temperature. The engine load is sensed as a function of throttle valve position by a sensor built into the carburetor.