Shift Light: Description and Operation

PURPOSE
The first to fourth shift indicator lamp is controlled by the Powertrain Control Module (PCM). The lamp tells the driver to shift transmission into fourth gear on the next upshift.


CONDITIONS
The PCM illuminates the shift lamp, when:
- Engine coolant excedes 41° C (104° F).
- Vehicle speed is 12 to 18 mph.
- Transmission is in first gear.
- Engine speed over 608 rpm.
- The PCM verified above condition.
- Throttle position is less than 23 percent.

CIRCUIT OPERATION
This lamp is used to indicate to the operator when the Powertrain Control Module (PCM) has determined that it is necessary to shift from first to fourth gear.

Power for the lamp is supplied on circuit G5. This circuit is protected by a 5 amp fuse located in cavity 8 of the fuse block and is HOT in the START and RUN position only Power for the fuse is supplied on circuit A21 from the ignition switch.

Power for the A21 circuit is supplied on circuit A1. This circuit is protected by a fusible link located near the auxiliary jumper post on the left toe box.