You don't give much info here - do I gather that you have a trailer plug on your 4R but it's not working? Was it OE or aftermarket?
Besides the connector itself, it can be the wiring - or in many cases the "module". There is a trailer light module on most imports that convert the separate tail and turn lights into the single light trailer configuration. You can get the whole kit (module, wiring, and plug) at an auto parts store.
If you have a test light you can check the output of the plug and know if you just have a connection problem or electrical problem.
If you can leave more info, I'll try to be more help.
Steve