New Speedometer / New Problem

[Agit8or]

I'm trying to help son in law wire new tach and speedometer to '02 115 2 stroke over the phone. Original gages were Faria and are being replaced with Yamaha analog. Tach installation went in no problem, with the addition of an additional wiring harness. With the speedometer, when the new blue and black are connected to the wiring harness, motor trim will not work. Disconnect the wires and it works fine. Connect to the Faria gage and it works fine. Reconnect to the Yamaha and the trim and tilt doesn't work. Nothing but a light in the gage. How is this happening?

[boats.net]

The blue and black wires are the backlight in gauge and should connect to same blue wire as on tach. You must have used the wrong blue wire(the up trim wire, alight blue wire) connected to speedo.