Jeep YJ Wiring Harness | eBay Jeep Wrangler yj engine wiring harness. all plugs and wires are in good shape removed from a running 1995 jeep wrangler with a 2.5 motor and an automatic transmission and a/c. Jeep Wrangler yj 1992-1.. JEEP WRANGLER YJ 87-90 2.5 4 CYL ENGINE WIRING HARNESS SEE AD . $139. Jeep Chassis Wire Harness - Engine & Transmission Wiring The purpose of a Jeep YJ wiring harness is to deliver electrical and other information to places your rig needs it. Many of the Jeep's systems have their own wiring harnesses. For example, your rig has a Jeep transmission wiring harness and an engine wire harness assembly. Unfortunately, over time, wiring harnesses can wear out.