The Shifter sensor or Range Switch is important for the TCU to select the correct shift pattern for each shifter position. This is a requirement of the transmission. It will indicate to the TCU which gear may not be exceeded. For example, if the shifter is in position 2, the TCU will not shift above 2nd gear unless it is allowed in that position. It will also tell the TCU to engage engine brake clutches etc. this switch is calibrated in the software.

The Shifter sensor is normally situated on the transmission where the shifter lever enters the transmission. Some transmissions do not have this sensor and it may be situated in the shifter itself. Other transmissions have hydraulic switches inside the transmission. These switches may only operate when the engine is running like GM 4 speed transmissions. If there is no sensor available, you may connect the sensor wire to the reverse light or a reverse ground switch. The TCU must know when it is in reverse to prevent shifting forward gears. This is an option for first generation 4 speed boxes that were not very complicated.

There are two different types of sensors. Analogue and Digital. The TCU requires an analogue signal that can be calibrated. If it is a digital sensor, Spitronics has a converter board that convert the signal to analogue. The digital switches can be serial or parallel switches so we designed 2 different converter boards. The type is also listed with the harness numbers as well as the diode boards on the top label of your drawing. Make sure you have the correct ones before wiring.

Shifter Converter Drawing

Spitronics Shifter
The Spitronics shifter has a serial shifter switch that convert the positions to analog signal by a series of resistors with progressive values. The TCU will measure the resistance and then calculate in which position it is. Note that Orion has a 1 K pull-up resistor built into the harness because the hardware is also ECU capable.

GM Shifter sensors:
The GM transmissions have parallel pressure switches that connects to oil channels inside. The switch pattern indicates position of the shifter lever. Spitronics has a parallel converter board with progressive resistor values to convert this digital pattern to an analog signal. The drawing in the Example below is for the 5L40E.