Land Rover Repair: Ground fault with turn signal?

Question
Hi John, My lead in, is we rewired out pop up trailer, which is how I found the problem. After re-wire of the trailer, everything works fine when connected to our truck. I then connected the trailer to our 1998 Discovery, which appears to have a factory towing wire job. So when the LR is connected to the trailer, the left rear turn signal/brake/hazard has no response. On further inspection, when testing the ground it is hard to get a steady signal when checking resistance. When I check voltage for both turn signals, I get voltage but the left turn signal and hazard have a little less voltage than the right. Here is why I think the ground is not good. Just for kicks I also checked for voltage on the opposite signal than the one that was on. When the right signal is flashing, I get voltage bleed over to left side, but only slight. The Left side does not have any bleed over to the right turn signal. What next? If it's the ground I do not have an earthly idea where to check? what ever you can suggest would help. thanks, D.T.

Answer
There is no such thing as factory trailer wiring on a 98 Discovery.  All the trailer wiring is via aftermarket kits.  I suggest you look at Atlantic British or Rovers North and buy a new kit.  Assuming the regular rear lamps are all working that will surely solve your problem