GPS sender for speedometer

I bought the classic dash wiring harness with my gauges. It has a single gray wire labeled gauge lightts that splits into 6 wires on the gauge side of the harness, one going to each gauge. Do I just splice the white wire from the dimmer to that gray wire before it splits off for each gauge?

I also used classic dash. I believe that's how I did it, but it's been over 2 years now, so I can't be certain.