I have a 1999 Expedition with the factory 7-way trailer connector and I want to pull a 1965 Shasta '20' trailer. When I connect the trailer to the Expedition and test the wires, only the running lights and trailer brakes work correctly. When I turn either turn signal on, both tail lights of the trailer blink. When I put on the brakes, I hear the trailer brakes themselves (controller wired in) but I don't get brake lights. I don't have this problem with my '86 F250. I double-checked the wiring to be sure the trailer matches the Expedition. The only trailer wire not connected is for the brake lights because I thought the turn signal/stop combination would take care of it. Any ideas? Thanks much!