I have a 1996 Grand Cherokee limited with the tow package, 7 pin. I need to go to the 4 pin plug for the boat so I picked up an adapter. It has the led lights to show if its working. left flashes and stop and running lights light up but when I try the right I get two flashing lights on the adapter which I would guess is showing a problem.. Everything works stop, tail and left turn but not the right turn. Trailer lights are good I checked them with a different vehicle. I am wondering if the previous owner switched wires? Anyone have the factory diagram of what the wires in the 7 pin plug should be? When I took the factory plug out and checked it, it has colors marked on it but the wire colors do not match. Thanks

 

http://www.wkjeeps.com/wk_towing.htm
here is one diagram. sounds like a ground problem to me.