I too had problems with connections from the coach to my 13 Explorer, primarily being insufficient or lack of power to the explorer in order to keep the battery charged.
So I did a few things. First I eliminated the blue ox cable - too small wires for the requirements - and replaced it with a heavy cable with more robust gauge wires:
http://www.rvproplug.com/?m=4&s=147This works well and although there still some tension when hooked up, I haven't had a problem yet with it coming undone. Doing it again I'd probably get a cable like Steve mentions - cheaper and no coils, I.e.tension.
This meant changing the 6 pin plug on the Explorer to a 7 pin. Also I ran a 10 gauge wire from this 7 pin receiver to the battery (with isolator - used toad charge but any isolators should/will work.
http://www.lslproducts.net/ToadChargePage.htmlOn the Coach I ran a 10 gauge wire from the house batteries to the 7 pin receiver. Thinking here is the house batteries will be charged while driving (after chassis batteries) and then when plugged in overnight there will be a charge to the explorer batteries. Isolator here as well.
After doing this I haven't had a dead battery or any problems with lights. I use Air Force One for brakes.
Jeff