x2 I had to do this and wired 2 magnets inside the trailer tool box (dexter actuator) and didnt work... it has to touch metal to complete loop and not just to each magnet I zip tied a piece of metal and it worked perfectly. There spliced inbetween the white and green if I remember correctly

Just to clarify when you say "it" needs to touch metal do you mean the magnets? Also, the schematic I got from Dexter show magnets wired between white (negative battery) and blue (they don't show a green).

Then go by schematic that sounds right. Yes either bolt the magnets to the frame or stick a piece of metal inbetween and zip tie tight together I used a 1/4" 4"x4" flat piece and it worked fine.

Wobble, sorry for this late response, I missed your post.

The 3500 has a dash mounted control that lists 2 WD, 4WD and 4 WD, low.

We really don't know anything about the P/U or how it performs. However, after the control solution is final, we'll put it in service.

There is one surprise...Rear wheel liners are not available for Dual Rear Wheels. The only solution is spray on bed liner material. The spray on should offer some protection. However, a wheel liner should offer greater protection from rocks and be easier to wash. Perhaps the non-available wheel liner was an over sight and will be offered later.