buick grand national wiring harness | eBay www›Search›buick grand national wiring harnessFind great deals on eBay for buick grand national wiring harness. Shop with confidence. 86-87 GRAND NATIONAL TTA ENGINE WIRE HARNESS DETAIL KIT NEW 1986-87 BUICK GRAND NATIONAL ENGINE WIRING HARNESS DETAIL KIT. Detailing your engine wiring harness has never been easier using this kit. Included in this dress-up kit are seven different conduit sizes: 6mm, 9mm, 13mm, 16mm, 19mm, 22mm and 25mm.