Why does my 7 blade trailer wiring connector not work?

[Blacknight]

I have a 2007 Monaco Knight 40 DFT. I recently acquired a 2009 Lexus GX470 which I have been working on to set up for flat tow. The problem I'm having is connecting the motorhome to the Lexus to have working brake/tail and turn signals. I purchased two pig tales to avoid altering the Lexus system.( did not want to cut into the harness etc). I ran the four wires, white (ground), yellow (left turn), green (right turn) and brown (running lights). The first time I tried the setup the left turn signal, tail light and brake light worked fine. I then went to the right side, connected the pig tale and I got nothing-tried the left side again and it did not work. I went to the coach 7 way plug and found only 1 contact point had any power. I believe this is a factory Monaco installed 7 way plug- I replaced it because #1 the door was broken and #2 I thought maybe the wires were damaged inside the plug, but the end on the plug, it is sealed so I just changed it. I went on line to find out where the 7 wires go ( color code) and set the plug to that schematic. ( I just assumed Monaco would be set up the same way). I double checked everything, plugged in the cable to the Lexus and nothing! I put new bulbs in the Lexus-nothing. I then went back to the 7 blade connector with a bug light and only 1 blade had conductivity. I checked the wire from the connector to the chassis plug connector and found no broken of chaffed wires. We used the old plug last year with no problem so I'm stumped! Any help would be appreciated-Thanks Steve