Just picked up an old 19ft 1970 HaiCo travel trailer. When i went to replace the tow wiring plug it only has 5 wires. White ,black. blue, red,yellow . i cant find a wiring schematic for it and didnt have any luck figuring it out. Ran new wires and lights to get it home but would like to use existing wiring. Only a white White wire goes to all the clearance lights but isnt the white a ground?? same as the 7 pole wiring plug? apprecaite any help out there . im stranded way up here in C-a-n-a-d-e-r 