Since a lot of people like myself tow trailers that use the 7-round plug and all that is available as a plug in installation is a 4-flat connector I thought I would write up how I wired mine. As of right now I only have the lights and batter charge line hooked up, no brake controller yet. As soon as I can afford a decent brake controller I'll install that also. I apologize I didn't get pictures as I was doing the install but I hope you can get the idea from the post-install pictures and my description.

The parts I used are:
AB Trailer wiring kit - http://www.roverparts.com/Parts/9439A.cfm
Hopkins 4-flat to 7-round adapter - http://www.hopkinstowingsolutions.co...c_adapter.html
Hopkins Mounting Bracket for 7-round plug
3/8" OD wire loom
3/8" ID wire grommet (5/8" outside diameter)

Adapter and mounting bracket are available through Amazon, any auto parts store or RV supply store. Wire loom and grommets I picked p at Pep Boys. It is not necessary to do all the step I did. I wanted a clean looking installation so I did more than was necessary. These are the steps I followed but I'll tell how to eliminate steps if you want.

Step 1: I plugged in the trailer wiring kit from AB into the LR factory socket and attached the converter box to the inside of the access panel with the adhesive that comes already attached to the box. Then I cut the 4-flat connector off the converter box since I wasn't going to use it and it wouldn't fit through the hole in the body. If you want a more simple plug in installation route the wire out the cargo door and under the truck to where the round plug will be mounted.




Step 2: I drilled a 5/8" hole in the body and installed a grommet then passed the wires, wrapped in the 3/8" wire loom, through the hole. I also passed a wire for the battery charge line through inside the wire loom and attached it to the purple line found behind the access panel.

Factory wiring on the left, my wiring on the right.


Step 3: Since I cut the plug off the converter box I went ahead and cut the plug off the adapter and attached the 4 wires from the converter to the adapter, just matching the colors. The charge line that I passed down from inside the truck is attached to the black line on the adapter. If you are using the 4-flat plug then it simply plugs in to the 4-flat socket on the adapter. You'll need to find a solid ground point and attach the white wire from the adapter to it. (I still haven't got my ground wire permanently attached so I can't really suggest a good place but any metal surface will work. The blue wire on the adapter is for the trailer brake signal and is not hooked up since I don not have a brake controller yet.)

Step 4: I used the mounting bracket as a template and drilled holes in the bottom of the bumper to mount the 7-round plug. I used pop rivets to attach the mounting bracket to the bumper because I was too lazy to find sheet metal screws in my miscellaneous hardware drawer. The wires in the loom I attached to the factory wire loom using zip ties.



Any questions, feel free to ask. I'm sure I'm not real clear on some things or I skipped something.

 

I had a flat 4 in my truck when i bought it, also with a receipt from a LR dealer for install. First time i hooked up the truck went nuts. Flashers and headlamps doing what the wanted, the littlew green trailer in the dash was flashing. The fix was cutting out the box in the rear pillar. The dealer was nice enough to cut the factory harness way to short to repair.Anyone wire one up by just tapping into the lamps all oldschool with any luck?

 

Did you have any problems with the lights without a trailer hooked up? Yes you can tap the light wire directly to hook up a light converter box. If you don't have a wiring diagram let me know and I'll email you a copy of the wiring diagram from my repair manual. A universal converter will work and should include instructions that explain what each wire is for.