Shift Light: Description and Operation

PURPOSE
This light is only used in vehicles equipped with a manual transmission. It is illuminated to indicate that the driver should shift to the next higher gear for best fuel economy.

OPERATION
This light is illuminated when the ignition switch is turned to the ON position and should go OFF after the engine has started. Engine speed and load are what determines when the Powertrain Control Module (PCM) turns the light on.

The PCM will illuminate to indicate that the driver should shift to the next higher gear for best fuel economy.

The PCM will turn this light OFF if the up-shift hasn't occurred within 3 to 5 seconds of its initial illumination. The light will come back ON if acceleration has stopped and the engine RPM has entered the range of shift light operation.


NOTE: Once the vehicle has been shifted to its highest gear the light will not illuminate, due to the operation of a switch located on the transmission.


CIRCUIT DESCRIPTION

Circuits F87 from fuse 21 in the fuse block and circuit G5 from fuse 22 in the fuse block supply voltage to the up-shift lamp. Circuits F87 and G5 are HOT when the ignition switch is in the START or RUN position.

The Powertrain Control Module (PCM) provides ground for the up-shift lamp on circuit K54. Circuit K54 connects to cavity 54 of the PCM.