I'm about to begin installing the same kit in my 07, and am also wondering where that blue wire goes. My truck does have that blue harness, I'm assuming is for plug and play with the brake controller. Let me know if you have any luck figuring out where the blue wire goes. I've done searches and have come up with nothing.

 

Just finished install of this kit, sorry no pics. Install went well. I was hoping for it to be plug and play though. Really didn't anticipate having to remove a tail light and splice and solder. I did call the "stealership" to ask about the elusive blue wire that is ran into the cab via the fire wall. And was told that i need to purchase an adapter that plugs into the pre installed blue harness under the dash, then the blue wire is added and wired to the brake controller. I hope this helps. Ill update ya'll once I get the brake controller installed and working properly.

 

And to answer your question about the white/lt green wire, it is for the back up lights.

 

http://www.etrailer.com/faq_dbc.aspx[/quote][/quote]

With respect to the instructions provided in the etrailer website above. The following is more of a question, as I am looking into installing the OEM tow harness myself (my truck only has 4-Pole), as I just purchased the 7-Post OEM tow harness. Here goes... It is implied (using the instructions for "Factory Installed 4-Pole") that instead of having the blue wire run thru the firewall, you can hook up the blue electric brake wire to the wire at the wheel well(as shown in etrailer instructions). Which means that under the dash, you would pretty much plug and play the brake controller (after scotch lock connecting blue wire to the wire shown at the driver side wheel well). Is this a correct assumption? I would of course have the plug and play harness that is described and the brake controller.

Another question, assuming the above is correct, to test the circuit, would you depress the brake to test the wire. I am not clear on this part to "test the circuit". You would test the circuit for the blue wire to connect to the brake light circuit?

Thanks in advance.

 

Hey all. New member here.

Hate to bring up this old post but I am having a similar problem. I found this forum searching google (with no luck) for answers.

First I was just wondering if any of the original posters to this thread are still around and don't mind a question or two. Thanks.