Mercury - Analog Gauge Harness DTS Engine Link 84-8M0150539. OverviewThis 3-foot analog gauge harness plugs straight into the engine's 4-pin lead and feeds the basics-trim, coolant temp, oil pressure, and tach. It's short, clean, and meant for simple dash hookups without extra adapters or long wiring runs. On the water, it helps those gauges read steady and cuts out a lot of the flicker or dropouts you get with tired wiring. Easy hook-up, easy routing, and built for modern DTS engines.. Key Feat