Has anyone tried to wire in a 6 or 7 pole trailer plug on a a 97 F150 that was manufactured prior to 10/96? Apparently these F150's and the ones built after 11/96 have different wiring harnesses. I had no trouble finding the connector under the dash for the brake box but I am slightly unsure where to pick up / locate the wire for the trailer brakes at the rear of the truck. I purchased an OEM type cable from Draw-tite (Part # 20028) that was supposed to convert the factory 1997 4 wire plug to a 6 pole round plug which is what my trailer uses. This unit appears to be very well made but the connectors on this cable and the connectors on the rear of the truck (inside drivers side frame rail) are different. I can locate all of the wires needed to hardwire a 6 way plug, if needed, except for the wire (usually blue) for the trailer brakes. Does anyone have experience with this process and / or locating the trailer brake feed wire? I feel like this wire is somewhere at the rear of the truck since the connector is under the dash and the factory 4 way plug is at the rear as well. Any help or suggestions would be greatly appreciated.