Swapping out tachs for my /6 conversion - the 911 tach has left and right turn signals vs. just one light for the /4 tach. I've found the instructions to do this but I'm a little confused. The blue/white wire from the turn signal flasher feeds the single light on the /4 tach. The instructions say to split this to both lights on the /6 tach - then run 2 wires from the emergency flasher that feed the exterior front/rear lights.

If those 2 wires are feeding the exterior lights and the blue/white wire feeds the interior light - isn't that 2 positives feeding each other if I hook them all to the tach lights?

Click to view attachment

The blue/white wire to the flasher should be connected to ground. Power then comes from the signal lights.

As designed the indicator lights get power from the flasher and are returned to ground through the opposite turn signal lights which are off when the other turn signal is flashing.

Notice how the right indicator is connected to the left turn signal bulbs and left indicator to the right turn signal bulbs.

So after connecting the blue/white wire to ground, you will swap the left and right indicators in the tachometer.

Grounding the blue/white wire does make sense. Thanks for the tip!

That's the back of the tach...

Why would the relay need two grounds?

I didn't bother to ground the blue/white wire. Just disconnected it because the lights ground through the gauge. Works great!