Hitch Doc & Trailer Harness Installation
by Don Kuhlman

We installed a Hitch Doc trailer hitch on my Valk. As I now also have a set of Tourer hardbags (thanks Jim!), there’s a lot of hardware to hang out back. A helper is definitely recommended!

The only assembly problem encountered, in addition to the usual fender bolt happiness, was the two front (big) fender bolts supplied by Hitch Doc were ¼" too long. On my fender at least, the two captive nuts are not threaded all the way through and the bolts would bottom before everything was tightened up. It was easy enough to fix by cutting approximately 4 threads off with a Dremel tool and cutoff wheel and then redressing the end of the bolt over at the bench grinder. Be sure to run a nut or die down the bolt first to chase and clean up the threads afterwards. I suppose you could finish tapping out the fender nuts as well, but I didn’t have the right size tap and didn’t want the bolts sticking through the inside of the fender.

To begin, it’s easiest to remove the seat(s) and separate the fender halves to work on them. The front portion of the wiring harness is under the right side cover and uses individual male/female wiring connectors. The rear portion of the fender has a special connector that separates it from the front section of the fender. Pinch in on the release clip and pull the halves apart to separate. Remove the license plate, license plate bracket, and then the turn signal bracket. It is held on by two nuts on the underside of the rear fender section. As you pull the turn signal bracket loose, you’ll find more individual wire connections that need to be disconnected. Don’t worry as they’re all color coded.

TIP: Use a pair of needle nose pliers to gently grasp the individual plug and socket at the base of the connector for removing and installing. Don’t pull on the wires themselves. When reinserting, make sure they are fully seated. If the connection seems loose, gently squeeze the outside of the socket or female half of the connection with the pliers to tighten them up.

For a wiring harness, I’m using a standard 5-wire molded harness available at most auto parts stores. I’ve found them to be much easier to install and to be more reliable than the older style chrome systems where the wires screw into the pins. Besides, mine is hidden behind the license plate when not in use. I also always carry the ground through as I find it to be a much more reliable method than trying to rely on the trailer ball connection.

All of the wiring connections you’ll need, except one, are available at the license plate/turn signal bracket. You will only need to run an additional wire for the brake light. This will be the green wire with the yellow stripe. I broke into the harness at the gray connector that goes between the two fender halves at the back half. This way I can still unplug the harness and split the fender as normal. I cut the wire and added a length of 14 gage wire that was long enough to run back to the license plate bracket. I used a mechanical splice AND soldered it as well as this connection also runs the normal brake light. The rest of the connections were all done with normal mechanical connectors.

After the wire is installed and the splice is properly insulated (use heat shrink or plastic tubing and electrical tape), carefully pull the wire harness running down to the license plate bracket out of the guide under the fender. Run your new extra brake light wire in the guide and then reinstall the harness to hold everything in place.

Next, you’ll need to drill a hole in the back of the turn signal bracket so that the trailer harness wires can be installed. Be careful as it’s made out of chrome plated plastic. I used a 3/8" hole. I also installed a Back Off LED license plate frame and ran its three wires through the same hole. You’ll need to notch the license plate to clear the wires as they come through the back of the frame. I also ran both the Back Off wiring and the trailer harness through flexible plastic tubing to give them a bit more protection and to provide a more finished appearance. Then, where they come through the turn signal bracket, I’ve installed a plastic tyrap on the inside to provide some strain relief. I also found that I needed to remove the bendable wire clamp from the inside of the turn signal bracket to provide enough room for all the connectors. Some pliers and twisting did the trick here.

The actual wiring scheme is straight forward. For the trailer harness, it’s brown for tail or running lights, yellow for left turn signal, green for right, white is ground and use the blue for the brake light circuit. The Back Off LED uses black for ground, white for tail or running, and red for brake light. Put a female connector on the new brake light wire you just added. Make it the same length as the rest of the rear fender harness.

At the turn signal bracket, you’ll need to cut the ends off the blue and orange turn signal wires (leave their green ground wires intact) and the brown and green wires from the license plate light. Cut the wires right at the factory connectors to preserve as much wire as possible. Then strip and join the necessary wires using new male connectors. The "blue" size crimp connectors are large enough to get all the wires in them and will still fit into the female sockets on the factory harness.

Join the red Back Off wire and the blue trailer harness and put them into a male crimp connector. This will be the brake light circuit. Join the orange turn signal and yellow trailer harness. The green trailer harness and the light blue turn signal wire then go together. Join the green license plate light, the black Back Off and the white trailer harness wire together. This is the ground for everything except the turn signals. Their green ground wires plug back into the green double female connector on the harness. Then join the brown license plate light, brown trailer harness and white Back Off wires. This will be the tail or running light circuit. Then everything plugs back in following the color code for all the Honda wires with the exception of the new brake light circuit. And the neat thing is you can unplug everything and remove the turn signal and license plate bracket by just unplugging the connections.

 

 

If not installing a Back Off light, eliminate BO connections.

The hitch itself goes on between the saddlebag brackets, if present, and the chrome covers over the frame rails. Follow the supplied directions on the sequence of the spacers, i.e. bolt, washer, bracket, thin spacer, hitch, fat spacer and then into the chrome bracket, through the frame and into the fender. Multiply this times 4 bolts and as you can see, a helper is going to make a big difference. As always, start all the bolts and fasteners but leave them loose until you get everything installed. Also, I left the upper shock mounts tight to keep the chrome frame horn covers lined up. It left one less thing to fight. You can also leave your sissybar in place. I also found using my work stand was helpful but not absolutely necessary.

A word on the Hitch Doc unit itself is in order as well. It’s an extremely well made and finished piece. The chrome plating is exceptional and the bolt holes were precisely where needed. It also comes standard with a nice 1 7/8" chrome trailer ball already installed. The hitch platform also has two holes up under the fender for attaching the safety chains. I don’t know yet how I want to do mine although simple through bolts and nuts would suffice. It also looks like there’s enough room between the bottom of the fender and the hitch platform to add a National Cycle fender tip I have laying around. The hitch itself is barely noticeable with the saddlebags installed and the Back Off LED light is nice and bright with the brakes on. I mounted mine with the LED at the bottom so it wouldn’t be washed out by the license plate light.

That’s about it. It’s a good afternoon’s work for two people who aren’t in a big hurry. Hopefully some of these guidelines will save you some "engineering" time as well.

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