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ST2 brake module


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So I have a bit of a conundrum. I have been trying to figure out how to install an ST2 brake module on my Tracer 9GT+. 
Seems like it should not be that complicated the module gets it’s power feed from the positive 12v and is grounded by the negative , as the accelerometer senses the engine braking it fires a 12v signal to energise the brake light circuit. 
The problem is the signal wire from the brake switches to the brake light drops voltage when activated by the brake switch instead of sending an energised 12v signal.
So…the circuit is already energised and the ST2 is trying to send a 12v signal to the light nothing can happen…am I missing something?IMG_3865.thumb.jpeg.9fdbf1f30c9d32ba537854fce10711bc.jpeg

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All below is just a maybe.

The tracer has a brake light relay.  Is the brake light signal wire you are tapping into powered by the relay, or have you tapped into a brake light wire coming from a brake light switch before the relay?  So I think you should attach the ST2 "brake light wire" to the OUTPUT of the relay - the wire that attaches to the brake light near the physical brake light, the "position light wire" to an always on when ignition is on front position light 12 volt positive (or other always on 12v+ with ignition on source) and the "ground wire"  (obviously) to a good ground.


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You're right, that close to the light itself you should be past any relay (unless Yamaha did something really strange).  Do you suppose the wire color coding could be incorrect for a 2023 in the instructions provided to you by the manufacturer?

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I checked everything with a multimeter fir the connections listed everything seemed to be correct, except the the signal wire to the brake light was negative switching instead of positive…I’m going to build a little sub harness with another relay I think…I assume if I run the signal wire across the NC circuit and the signal wire from the ST2 to the coil, the ST2 could fire the coil and send a NO circuit signal to the brake light the same as the brake switch does…just have to wait for the plugs to turn up so I can start on it…

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