一开始怀疑是霍尔传感器，但转到不同位置测出来的电压都是一模一样的，这根本没法检测位置

发动机那边什么样的？

解决了吗，开始我也以为是像杜卡迪一样用是霍尔传感器，到处找文档，现在看来像机械触点？

这类型的叫做，非接触式齿轮位置传感器，采用旋转滑动触点，不会因碰撞和磨损而老化。

Triumph Gear Position Sensor For Newer Models
The gear position sensor for newer models has 7 electronic switches that are activated in sequence as the gear selector moves through the 1-N-2-3-4-5-6 positions. These switches connect increasing resistance values to electrical ground through a fixed resistor in the ECM module, and this creates a different output voltage for each gear. The computer inside the ECM module reads the voltage to determine which gear the bike is in.
The gear position sensor is designed this way to reduce the amount of wiring and the size of the connector and harness between the gear position sensor and the ECM. With this system, only 4 wires are required: one for the voltage, one for the neutral position (for compatibility with older designs), one for power, and one for ground. Connecting the switches directly to the ECM would require a minimum of 8 wires.
The sensor for older bikes has a three wire sensor in stead of four. These sensors are likely based on a variable resistor element instead of the switched resistances of the new models. It is possible that Triumph moved to the switched version because of improved longevity and reliability -- variable resistor elements are more prone to wear.
The ECM uses the gear position information to operate the ignition, adjust the timing or fuel mixture, and the neutral light. The ECM module in Triumph motorcycles also transmits the gear information onto the CANBUS network within the bike's wiring. The diagnostic connector connects to the CANBUS network with a proprietary communication protocol and not as OBDII. The Gearingo gear indicator has the internal circuity to listen to the CAN communication, and having deciphered the messages, can display the gear for the rider.
OBDII communication is available on the diagnostic connector, but as a K-LINE signal and not CANBUS
We took apart a Triumph gear position sensor to see what is inside of it, see the picture in Figure 2 below. The sensor has the following basic components:
Sensor housing with two mounting ears.
Rotating disk with a small magnet that attaches to the bike's gear selector assembly with the camshaft housing.
Printed circuit board that has 6 Hall Effect magnet sensors which pickup the location of the magnet.
Cable and connector that connects the sensor to the main connector on the ECM module. This cable has a braided sheath on it to protect the wiring against heat and abrasion.
The simplified schematic in Figure 3 below depicts the gear position sensor's internal circuit. The transistors marked Q1-Q7 are actually hall effect switches that are positioned in a circular pattern around the center of the unit so that the small magnet rotates over and activates them in sequence.
来自技术文档，实际上还是霍传感器，由Q1-Q7不同的晶体管，由磁铁激活不同电压送到ECM来判断档位，高级，但是没有机械的便宜好维修，坏了只能换，维修成本高。