1978 chevy truck wiring harness | eBay Save 1978 chevy truck wiring harness to get e-mail alerts and updates on your eBay Feed. + Items in search results. 1978 Chevrolet Pickup Truck C10 CHEVY UNDER DASH FUSE BOX Wiring Harness OEM GM . Pre-Owned. $179. or Best Offer +$12 shipping. 1978 Chevrolet Silverado Underdash Fuse Box Wiring Harness #1 Uncut Truck. Wiring harnesses for classic Chevy trucks and GMC trucks Wiring harnesses, wiring harness clips, and obsolete parts for classic Chevy trucks and GMC trucks from Classic Parts of America.