[magnumv8]

We do these everyday at the shop so if you haven't solved it yet......if your truck has factory trailer wiring you should be fine there.....if the trailer still has the industry standard color coded cable (wiring) the trailer plug on the trailer gets wired like this with a 7 blade connector....to make it easy ignore the colors printed on the plug and socket and go only by the blade numbers (very small).....

#1....white...10ga wire...ground
#2....blue....12ga wire....trailer brakes
#3....brown....14ga wire.....tail lights,license plate light,marker lights
#4....orange or red....10ga wire....battery charge wire
#5....yellow......14ga wire.......left stop,turn signal
#6....green.....14ga wire.......right stop,turn signal.....
#7.....aux....can be used for whatever,leave empty

if everything is cool from there you said that the previous owner replaced the tail lights (stop/turns)......after double checking everything so far and the ground connection on the trailer frame here is what I would check next.....

The stop/turn light pigtails are 3 wires...one white(ground wire) one black(marker light wire) and one red(stop/turn).....if the previous owner replaced this pigtail it sounds like this is where the problem may be....it sounds like he has the marker light of the pigtail connected to the stop/turn on the trailer wiring,this explains why your trailer tailights blink dim and the marker lights blink also when you put on your turn signals....this would also give a feed back through the trailer plug into the truck causing it to do some strange things too.....


let us know what you find out.....

D L Rambo