Mercury - VesselView 502 Power Harness SmartCraft Power & Data Harness 84-8M0111669. Overview. The Mercury VesselView 502 Power Harness (84-8M0111669) delivers power and SmartCraft data from your junction box to your VesselView 502 display. It's the key link that keeps your system running - carrying both power and communication signals through one clean connection. This OEM harness comes standard in complete VesselView 502 kits but is also available separately for replacements, upgrades, or cust