RAM 3500 Truck 2WD V10-8.0L VIN W (1997)
Overdrive Switch: Description and Operation
Circuit Operation
CIRCUIT OPERATION
Automatic transmission equipped vehicles may have an overdrive switch. The operator disables or enables overdrive when the switch is depressed.
The overdrive system consists of a switch connected to the Powertrain Control Module (PCM) and an overdrive ON/OFF indicator lamp.
If overdrive is currently enabled, it is disabled when the operator depresses the overdrive switch. Also, if the operator already disabled overdrive,
it is enabled when the switch is depressed.
Circuit T6 from the overdrive switch connects to cavity C13 of the PCM and provides the overdrive signal. Circuit Z3 provides ground for the
switch.
In the START and RUN position, the ignition switch connects circuit A1 from fuse 3 in the Power Distribution Center (PDC) with circuit A21.
Circuit A21 connects to the bus bar in the fuse block that powers circuit F12 through fuse 11. Circuit F12 supplies power for the overdrive
ON/OFF indicator lamp. The PCM turns the overdrive ON/OFF indicator lamp ON or OFF by providing a ground for the lamp on circuit T18.
