Grand Cherokee 4WD V8-5.2L VIN Y (1998)
Overdrive Switch: Description and Operation
The overdrive OFF (control) switch is located in the instrument panel. The switch is a momentary contact device that signals the Powertrain Control
Module (PCM) to toggle current status of the overdrive function. At key-on, overdrive operation is allowed. Pressing the switch once causes the
overdrive OFF mode to be entered and the overdrive OFF switch lamp to be illuminated. Pressing the switch a second time causes normal overdrive
operation to be restored and the overdrive lamp to be turned off. The overdrive OFF mode defaults to ON after the ignition switch is cycled OFF and
ON. The normal position for the control switch is the ON position. The switch must be in this position to energize the solenoid and allow a 3-4 upshift.
The control switch indicator light illuminates only when the overdrive switch is turned to the OFF position, or when illuminated by the transmission
control module.
