PN#55540 SKU#1237 Custom Wiring. 4 Flat. Select Chevy Express. GMC Savana 1500, 2500, 3500, 4500. This custom wiring harness features a vehicle-specific design to perfectly fit certain years of the Chevy Express and GMC Savana 1500, 2500, 3500 and 4500 (to verify vehicle compatibility, see the CURT application guide or use the Vehicle Lookup on the CURT website). It uses OEM-compatible connectors to “T” into the vehicle’s taillight assembly and provides a standard 4-way flat output to power the taillights, brake lights and turn signals on your trailer. To complete this custom wiring harness, it comes with a rubber dust cover. This cover keeps the connection points clean and well protected when the connector is not in use. Once installed, the connector can also be conveniently mounted on the vehicle’s trailer hitch receiver tube, using a CURT Easy-Mount connector bracket. The bracket mounts onto the trailer hitch with no drilling required, and its powder-coated steel construction provides a solid attachment point for plugging in the trailer wiring.