I have a friend who is asking me to install a trailer hitch, and I guess this would include wiring too. His is an 08 SC Element.

I'm having him get the hitch, and going from there. I'm an experienced auto mechanic, but have moved on to locomotives. (more pay, benefits, blah blah)

Any tips on wiring for the trailer harness if there is one? he wants a pop-up camper to tow possibly. Does honda have a factory harness back there I can look for to branch into?

He also wants a secondary battery added in so he can run little things. I've read a battery isolator switch is needed to keep the battery from using the other's voltage, but let the alternator still charge it.

I reeeeally don't wanna burn anything up in his car, as I'm doing this on the side. Any info you guys can provide will be awesome. I can solder, and I always use heat-shrink, no crappy tape and bent together wires here. Thanks!

 

I'll include the other years, in case someone does a search for this topic. But the one you need is the third link:

http://www.handa-accessories.com/ele...ementhitch.pdf 2003-2004 Element
http://www.handa-accessories.com/element/05hitch.pdf 2005-2006 Elements
http://www.handa-accessories.com/element/07hitch.pdf 2007-2008 (Perhaps, 2009

As for the second battery, if it's still fairly new and in tip top condition, just add another parallel to it (Since it's a 2008 MY, shouldn't have a problem if he gets another battery). It will reduce the need for a battery isolator. Although the drawback is if he runs his "little things" too much, he can kill BOTH batteries, and his alt works at charging both at the same time, as opposed to individually with an isolator, though many people say it isn't a concern unless high draw is being made.
I'd go that route, and advise him of it. The isolator available comes in different forms; switch, diode, solid-state relay, hybrid. You have to decide which one you're using, and which one best fits the application.

Good luck, though it shouldn't be hard for you, considering your background.

 

I would never tow any camper with a CR-V or Element...
Just not enough towing capacity