Monster 696 speedo sensor connector - what do the 3 wires do

[MrsC_772]

Primus (my original 696, bought in 2009 though a 2010 model) has once again decided it doesn't want me to know how fast I'm going or how far I've gone. Indicated mileage just over 80k, actual mileage now around 82k ish.

Having swapped the speedo sensor for a new one (I think I might now be on the 5th one), it stopped indicating speed and adding miles to the clock only around 40 miles later. This makes me & Andy think the problem may lie in the bike wiring, not the speedo sensor itself.

The wiring diagram in the 696 workshop manual shows 3 wires running from the plug to which the speedo sensor attaches:
- one runs to the ECU pin H3;
- 2 go to the clocks, to pins 4 and 19 in the connector at the back of the clocks.

It might help me (or any garage I decide to pay to take a look at the bike) if we can narrow down which wires might be broken or connectors furred up in diagnosing the problem.

Anyone know what the 3 wires do? Supply, ground and signal?

[Mr Gazza]

Hello Eleanor. Good to hear you're still around and putting more miles on your Monster(s).

Regardless of what the cables do, they still have to conduct electricity properly.
So if you know where both ends are and what colours they are, the first step is to test each one for continuity from top to bottom and make sure there is little or no resistance.
Also check that they don't connect to either of the other 2 cables.
If there is a problem with one or more, then the easy solution might be to just run a new cable beside the old.
Connectors can be very deceptive, they can look okay but not conduct anything. I had this with the plugs on the top of my injectors, looked fine but nil connecto! Hence why you need to test the continuity from speedo/ECU to the last connector before the sensor.

[Nickj]

Power
Ground OR Signal Power
Signal Output

Depends what they are using for the sensor.

But as Mr Gaza says the wires have got to work as wires so they need testing no matter what the sensor is doing.

I know that your gagging to know the difference between two and three wire sensors like this so ...
2-wire sensors are operated in series to the connected load. There are no separate connections for the load circuit and the voltage supply of a 2-wire sensor. So it is acting like a switch. ON OFF ON OFF
3-wire sensors are sourcing, type "PNP", or sinking, type "NPN", with separate connections for the power supply and for the output. So it has a seperate supply on the load wire. A bit like a transistor but still works like a switch. ON OFF ON OFF

Knowing isn't often a great help LOL