I have finally wired the trailer hitch.

The first pic show the cables coming from the left of the trunk where the hitch 'box' is located by the air pump, going into the tail light housing via a small factory hole. I added a grommet for protection.

I was not ready to hard wire it all, so I decided to add a disconnection plug in between the box and the car harness.

Also I decided to split wires from the rear tail light instead of tapping in the car side harness. So if something get screwed up, I can remove it all nice and clean.

I used a cheap trailer plug for connection, that is all I could find at my local auto parts store.

I opened the cable for the split and soldered them, then use electrical tape. Might be overkill but I hate the plastic splitter connectors.

FYI:
Green is turn signal
Red is tail
Black is brake

Luckily there is enough space behind the tail light to hold the additional wires and the hitch plug.

My hitch 'box' being on the left side of the trunk I routed the positive battery cable from the left side to the right side of the trunk using the top engine bay shield (last pic). it flex just enough to allow a cable to be jammed in there, this way it goes all the way to the right side very close to the battery positive connector.

It took me forever to do this correctly but it is a clean job now.

philooo,

I need to wire up for a tire trailer, too. I have a 997.2
1--how is yours working?
2--did you use the converter kit that you showed in your post, or did you switch to something else?
3--did you end up using two lights per side of the trailer, or just one light per side?
4--where did you pick up your 12 volt power from?
5--please tell me anything else you can think of. You're the experienced pro now; see one, do one, teach one. I know nothing about this subject, since I have never had a trailer before, so anything you tell me will help.
Thanks,
Jim

Well, actually I see you answered most of these questions in the preceding post. Anyway, please advise me on anything you can think of that will help. I am no electrician!

1/ my system works fine
2/ I did use the converter I mentionned, uhaul stuff.
3/ I did not modify my trailer and kept the one light per side.
4/ I did pickup the 12V power from that terminal on the right side of the engine. still bums me not to have found a switched power. I hope the converter does its job and not comsume power when lights are not on.
5/ For me really the biggest thing was to tap in the rear tail light wire harness but with patience you can do it easily. I forgot If I posted the wire colors and their meaning or not. You can tell which wire is which by looking carefully what bulb they link to but it is much easier with the diagram.
I did not wanted to touch my right tail light, so at this time everything work but the right turn signal. I will use the trailer only to go to the track, I think I can make it by without one turn signal. it bothers me a bit but I want to keep the number of new wires to a minimum.

Once you get the proper wire harness from uhaul and made the decision to tap into the tail light harness everything make sense. I wish I could have found a better 'electric plug' to connect and disconnect the converter from the tail light harness, but the trailer plug works fine even though it is bulky it fits in the tail light location.

good luck with your install, report here is any problem, I'll be watching ;)

Philooo,
A couple of questions.
What did you use to cut the bumper to make room for the hidden hitch?
Where did you install/hide the trailer wiring electronic box that you got from U Haul?

I did put the uhaul electronic box right in front of the secondary air pump. the air pump mount is offering plenty of space to zip tie it.

To cut the bumper and the heat shield I used a dremel

My hitch install
 

Philoo,
Thanks to all your help, I completed my hitch install this weekend. I have included a few photos to show you a couple of the modifications to your work that I did. One, I found some flexible adhesive heat shield to apply to the stock heat shield cut, as I was worried about heat on the bumper during long weekend DEs. Second, I found an LED light magnetic telescoping holder that made the bolt install easier as you could see the light as it neared the drill holes. All in all it took me about 4 hours including the trailer harness. You will see the wiring harness sits neatly above the hitch in my setup.
I never could have done this without all of your help!!!:cheers::thumbup:

Excuse me, osteoman, it's philooo, not philoo. C'mon, details, man!
I also found philooooo's posts to be helpful.
One observation about fishing those bolts through the rear of the bumper:
I removed the metal bumper completely off the car in order to change those weak stock bumper supports to the older style, stronger "shocks." I had complete access to the rear of the bumper, so none of the "fishing" of those bolts, nor the metal tabs that are welded onto the bolt heads were necessary. Removing the bumper support was a breeze (two bolts). I guess you guys are not removing the bumper and replacing the bumper support "shocks"?
Also, I'd like to contribute my wiring "discoveries" to philo's instructions.
FOR MY 997.2 (hopefully, all 997.2's are same) :
The LEFT tail light wire harness plug that plugs directly into the left tail light has numbers stamped into it for each wire.
The brake light wire is black and yellow wire; the #1 pin on the plug.
The turn signal wire is black with grey stripe; the #4 pin on the plug.
The running (tail) light wire is grey with black stripe; #6 pin on the plug.
The RIGHT tail light wiring harness has to have the Green trailer wiring harness wire connected to the right TURN SIGNAL wire. This wire is the green and black wire; the #4 pin on the plug, on the RIGHT tail light.
Again, thank you phil000.

I am glad my post was helpful ;)

Can you guys post the way you connected to the positive battery wire ?

My connection is not that great so far. I was not able to unscrew the screw located in the engine compartment as it is super tight and I am afraid to apply more force to is as it looks strange and may have a special thing to it.

Please post pics of how you got your positive connection ;)

I read somebody's post where he hooked his 12 volt power wire to the alternator. The starter motor also gets direct power from the battery, and both the starter motor and alternator are right there in the engine compartment. I did no such simple and wise thing, 'cause it didn't occur to me. I ran the power wire all the way from the battery to the left rear of the engine compartment. I removed the undertrays underneath the car and zip tied the wire to all the other wires and lines that I found running under there. Be careful to keep all wires away from anything that gets hot. Sorry, no pics.

Hey Guys,
Am I missing something? My wiring kit from U-haul only required a negative ground and positve connections to the tail lights. It seems to work great and as my trailer is using LED lights the power drain is minimal when being used at best. As you can see in my pictures I just connected the ground and ran the one wire to the right side lights for right turns and the other 3 wires to the left side for everything else.

Philooo, sorry about the typo on your username, spelling was never my strongest subject in school. :roflmao:

Your wiring kit did not have a black main power wire???
Jeeez, that would have made it a lot easier!
I used a UHaul kit, too. The converter box and the wires look just like yours, except mine has a very long (10 or 12 feet long) thick, black power wire that the instruction said to hook to battery power.
Maybe your kit is meant to be used only with LED trailer lights which, as you said, do not draw much power. That would make sense. I never intended to use standard trailer lights, so I could have used your kit, or rather, I did not have to hook up that @%^**&%$ black wire in my kit. I'm feeling a little sick now.
Well, this is excellent info for the next guy.

Phil,

Did you get a new car?

no new car for me, I decided to keep the 996. Great deal for the money right now. Afraid of the dreaded engine grenade but I decided to stick with it. The chance of wrecking the car myself being a lot higher than blowing the engine anyways :)

I saw the red car in your avatar and thought you might have traded yours or had it painted.