Thamer, one was grey and one was brown. They both go to the ecu, but they have in-line connectors before they go into the ecu. I disconnected the grey wire which is the wire coming off the front brake lever at the in-line connector. I disconnected it and I don't get a check engine light any longer. Jarel told me to do this. I tried tracing the rear wire but it goes behind the plastic thing that holds the ecu to the bike and I didn't feel like tracing that one. Just disconnect the one coming off the front brake lever. If you use the rear brake, you will have to trace that one as well.