Transmission Internal Mode Switch

The transmission Internal Mode Switch (IMS) is a multi-signal switch assembly attached to the lower control valve body. The IMS consists of a set of stationary contacts and a set of sliding contacts. The manual valve link assembly connects the sliding contacts to the manual valve. Electrically, the stationary contacts are connected to ground through the IMS ground circuit and the sliding contacts are connected to the Powetrain Control Module (PCM) through four IMS signal circuits. The signal voltage at the PCM is high, ignition voltage, when a signal circuit is open and low, zero volts, when a signal circuit is closed to ground. Each gear selector position grounds one or more of the signal circuits in a unique pattern that enables the PCM to determine gear selector position.