# Sensors – SSP 237 Manual Gearbox 02T

> Speedometer sender G22 (Hall sender on the differential housing) and reversing light switch F4, with their circuits.

- Web page: https://catalog.polo.blue/self-study/ssp-237-manual-gearbox-02t/sensors/
- Original document (PDF): https://cdn.polo.blue/files/SSP237-Manual-gearbox-02T.pdf

## Road speed display

![Road speed display (237\_013)](https://catalog.polo.blue/instructions/ssp-237/73556d1a269a038c.webp)

An impulse sender wheel milled in the differential housing generates the signals that speedometer sender G22 requires to determine the actual road speed of the vehicle.

Speedometer sender G22 is inserted in a drill hole in the gearbox housing from the outside.

![Road speed display (237\_015)](https://catalog.polo.blue/instructions/ssp-237/7bd0c0a9c1e90d31.webp)

The sender operates according to the Hall sender principle. The electrical impulses generated by the sender are transmitted to the control unit in the dash panel insert. Here, the signals are conditioned for the actual road speed and mileage display.

Advantage: Ultra-high display accuracy, smooth running, temperature resistant.

### Electrical circuit

![Electrical circuit (237\_014)](https://catalog.polo.blue/instructions/ssp-237/e85b59f369b3b8db.webp)

- **D +15** Ignition switch, terminal 15
- **G21** Speedometer
- **G22** Speedometer sender
- **J285** Control unit in dash panel insert

## Reversing light switch F4

![Reversing light switch F4 (237\_018)](https://catalog.polo.blue/instructions/ssp-237/5535bfbdbfe0df1a.webp)

The reversing light switch is screwed into in the gearbox housing at the side.

When reverse is engaged, the switch is actuated by a rise on the reverse gear selector plate.

The electrical circuit for the reversing lights is closed.

### Electrical circuit

![Electrical circuit (237\_020)](https://catalog.polo.blue/instructions/ssp-237/b4dd2dbf9252874c.webp)

- **D +15** Ignition switch, terminal 15
- **F4** Reversing light switch
- **M16** Reversing light bulb, left
- **M17** Reversing light bulb, right