On my Vectra there is a parasitic transformer in that cabinet that powers the GPS DVD-reader (for loading updated map info). The wire then wraps around/behind the overhead row of cabinets, crosses just above the windshield, and connects to the DVD reader in the cabinet above the driver's seat. I unplugged it, too. \ken
Ken & Deb (WIT Club, FMCA, SKP, Harvest Hosts, and grateful volunteers with SOWERs)
2005 Winnebago Vectra 40FD w/400ISL and Allison 3000MH on Freightliner's Evolution chassis, Onan QD7500, 1000w Renogy solar, BlueOx tow gear, and 2015 Cherokee TrailHawk toad.