Homepage - Ag Express Ag Express provides solutions that help you compete in today's ag environment. We specialize in the sales, service and support of electronic equipment used in agriculture. We also provide custom wiring harnesses and interface solutions for OEM machinery, controllers and implements.Repair Order Form · Contact · Store · Precision Catalog · Location Information · Overview Custom & OEM Wiring Harness - AG Electronics Inc Custom & OEM Wiring Harness. Custom building a planter? A small manufacturer looking for a unique wiring harness, but do not have the numbers to interest a large harness house? A large manufacturer looking for a company that knows and understands ag-electronics with the capability of building a superior product for you?