Installing Ecohitch and Tekonsha ZCI wiring on 2014 Allroad

[jerhofer]

I am a station wagon guy. I love the utility and that a station wagon drives like the car it is. Along with that, I am not a truck owner. When I occasionally have to haul something that is either large or dirty, I prefer to use a small utility trailer. Over the years I have installed a number of hitches on various cars and wagons. It was time for the Allroad to be hitched!!

My hitch of choice has been Curt. They are well made and priced well. My biggest beef with them is that they hang low and are exposed. On my last hitch installation, a 2010 Cadillac CTS wagon, the hitch would often drag when traversing dips. During my search for a hitch for the Allroad, I came across the Ecohitch by Torklift Central. I watched their installation video and loved the fact that the hitch is mostly hidden. In spite of costing nearly double the price of a Curt, I ordered one.



Like the Curt, the hitch was powder coated. The Ecohitch had a textured appearance and appears to be well made. The written instructions were very good with some small photos.

The first instruction says to raise the rear of the vehicle. Having a lift in my garage made that an easy task. (Increasing garage envy would be that my garage has AC, kind of important in August in North Carolina. Seventy-five degrees and little humidity inside the garage.) Having read the instructions ahead of time, I knew that removing the rear wheels would help.

Next up is removing the side panels on each side of the rear cargo area. The passenger side has a 12V outlet that has to be unplugged before you can move the panel completely out of the way.
















The back up sensor plug must be undone and the pigtail to the rear bumper cover pushed through the access hole.











To remove the taillights, a large black pin must be unscrewed. Just below that pin is a rubber grommet. Once that grommet is removed, a 10mm hex nut will be found that attaches to the rear bumper.








The taillights are located by two pins on the front edge. Push the taillight to the rear to dis-engage the pins and then remove the electrical connector.




There will be three torx screws in each rear wheel well that attach the inner fender liner to the rear bumper cap. Remove them and a fastener above them that slides off by applying a screwdriver to one side. Underneath the rear bumper cap will be found three more screws that need to be removed.







In the taillight opening will be found a white guide pin. Pry this pin up and then release the guide pin hinge by pushing it towards the center of the car. This releases the bumper cap from the body.












Gently unsnap and remove the rear bumper cap starting at the wheel well corners while working your way towards the center. It comes off fairly easily at this point. Keep in mind the pigtail for the back up sensors on the passenger side.








Remove the spare tire. With it out of the way, remove the plastic liner around the spare tire opening. There are four torx screws on the rear ledge.







Remove the four cargo tie downs and lift off the two side rails. This exposes a bolt on each side that will be used later on.








And the pile is growing.




Remove the 10mm nut that attached the rear exhaust hanger after supporting the mufflers.

[jerhofer]

Now the heat shields can be removed. Once they are off the car, a two inch hole needs to be cut into each of them. Mark a point five inches from the center of the forward most hole to the center of the new hole.








Nearly every hitch I have installed uses a bolt fisher.




A bolt fisher works by screwing the end of the bolt fisher to a carriage bolt that has been placed through a plate washer of some kind with a square hole for the carriage bolt. The bolt and the fisher are fed into a hole and then pulled through another hole with the bolt now placed with the washer in position. In this case, feed the coil end through the forward most hole in the frame rail above the muffler and pull it out of the middle hole. The second bolt is then inserted into the middle hole and then pulled back out of the same hole. We now have two 1/2 inch bolts poking through the two front holes. Unscrew the bolt fish from the bolt once you have them in place and be careful not to push the bolt back into the hole.













Now we remove the 10 mm bolt next to the tie-down that I mentioned earlier. It is replaced with a longer bolt that will extend down below the frame rail and will be come the third bolt for mounting the hitch. Torque these bolts to 45 ft lb.






Re-install the heat shields. Raise the hitch into position while being careful to not push the mounting bolts back into the hole. Since I had the mufflers supported by stands, I used two more stands to support the rear of the hitch while I rested the sides on top of the mufflers. I gradually raised the rear of the hitch with the stands and then affixed the serrated flange nuts on the 1/2 inch mounting bolts. The M10 bolt is secured with a 2"x2" plate, a flat washer, a lock washer and the nut. The two half inch bolts are torqued to 75 ft lb while the M10 bolts is torqued to 45 ft lb. The muffler mounts can now be affixed.






On the stainless steel part of the rear bumper cap, a center section must be removed for clearance for the hitch. Measure 5 1/4" from the tip of the center mount hole towards and then make the opening 4" wide. Since this is stainless steel, it is pretty tough. I used an air cut off saw to remove that section. Apply the included Trim-Lok around the opening. Once I had the bumper cap in place, I trimmed the excess from the Trim-Lok.









This is what it looks like when finished.

[jerhofer]

I bought the wiring kit on etrailer. There were two options for my 2014 Allroad. One was a conventional wiring kit which would involve soldering or otherwise connecting wires into the existing system.

The other option was the ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit. No wiring splices are required with this kit. The wire with the desired signal is placed into the connector which uses induction to read the signal. Again, this kit was more expensive then the traditional kit but it promised to work well with today's electronics.







As I usually do, I broke out my voltmeter to deduce which wires had the voltage I was looking for. I turned on the left turn signal, went to the left rear turn signal connector, and found that I was getting an alternating 12V signal on both the Grn/Blk and Gray/Blk wires and was also getting a 5.5V signal on the solid gray wire. So three out of the five wires had voltage to them.

The right turn signal showed Grn/Blk and Gray/White wires with the alternating 12V signal and the 5.5V on the solid gray wire.

Applying the brakes gave the same voltages on both sides as listed above.

Turning on the running lights resulted in a 12V signal on the solid gray wires on both side with the Gray/Blk and Gray/White wires showing 5.5V on both sides.

I could see now that clearly the solid gray wire was the running light source, but I was confused about which wire to select for the turn signals and brake lights. So I called Tekonsha. The gentleman there was very helpful. Basically what their system is looking for is a change in amperage. It was obvious that the brakes and turn signals were all being controlled together. He didn't think it mattered which of the Grn/Blk, Gray/Blk or Gray/White wires I chose.

The way their system works is, once you place the appropriate wires in their connectors, you must place the control module in the "learn" mode. You do this by removing the 15Amp fuse for the module, start the engine, and make sure all of the lights are off.

You then insert the fuse which initiates the "learn" mode in the module. Now one simply turns on the running lights for five seconds, then each of the turn signals for five seconds and apply the brakes for five seconds. The module calculates the amperage used for each function and sends the appropriate signal to the trailer wiring harness. It worked like a charm. The trailer lights were bright and there were no fault codes showing on the dash.




The module must be wired to a 12V constant source. Luckily our Allroad's have the battery underneath the spare tire so it was a short run to the module. I decided to place the module behind the panel in the left rear corner. To get the 12V wire and the ground wire to that area, I loosened the three 10mm nuts on the speaker enclosure in the spare tire well. I then ran the wires under that speaker back to the rear and tucked them under the rear trim piece. The wires for hooking up the right rear lights also were tucked under this trim piece to run to the left side.

















Since there wasn't a lot of room to access the taillight wires inside the car, I pulled the wiring harness through to the outside of the car. This is where I attached the module connectors. Be sure the arrow on the connector is aimed towards the taillight. Once you have the wire placed in the connector, you snap the cover closed. Once you are sure everything is working, the supplied adhesive backed foam is wrapped around the connector to hold everything in place.






There are four of these inductive connectors which are clearly marked: Left Turn Signal, Right Turn Signal, Brake, and Running Lights. Since the brake and turn signals use the same signal, the Brake connector was not used. I ran the left turn signal and running light connectors to the left side while the right turn signal connector was run across from the left side to the right side, as described above.


To run the trailer wiring harness from the module to the hitch, I slit the left side taillight wiring grommet and slipped it over the four wire trailer harness. I then ran the wires along the rear of the car to the hitch and zip tied the wires to the hitch, to a support and to the vent cover. With everything in place, I re-installed the grommets and applied rubber caulk to the left side grommet where I had slit it.












Now that the wiring was complete, it was time to re-assemble everything by reversing the steps above. That always sounds easier said than done, but, in this case, everything all went back together relatively easily. I have used the trailer a couple times and everything has worked well. I am very happy with the hitch as nothing hangs down and would recommend this hitch to anyone thinking of adding one.

[billybob_lee]

Fantastic write-up! I was planning on getting this hitch but wasn't sure how it would look or what it would take to install it. Your photos and step-by-step walk through really convinced me to take the plunge. Thanks!


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[adt]

Thank you for the great writeup and pictures. I am very much interested in this hitch.

A couple questions... Is that a 2" receiver or the 1-1/4"?

How much ground clearance is under the receiver?

Thanks,

Adam

[jerhofer]

Thank you for the great writeup and pictures. I am very much interested in this hitch.

A couple questions... Is that a 2" receiver or the 1-1/4"?

How much ground clearance is under the receiver?

Thanks,

Adam

You're welcome!

It is the 1 1/4" hitch and the clearance is 11 1/4".

[adt]

Thanks!

[billybob_lee]

I have a quick question about using the hitch and the parking sensors. I was wondering if pulling a trailer or using a hitch hike rack would set off the proximity/parking sensors. Is there any programming that needs to be done?


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[jerhofer]

I have a quick question about using the hitch and the parking sensors. I was wondering if pulling a trailer or using a hitch hike rack would set off the proximity/parking sensors. Is there any programming that needs to be done?


Sent from my iPad using Audizine

There is no warning noise but a fault shows up on the display screen. It goes away as soon as you toggle to another screen and doesn't come back until the next time you start the car.

[skis4hire]

Awesome write-up!!

Where did you get the carpeted mat for the trunk? I believe they have been discontinued since 2012 or 2013 :(

[skis4hire]

Also FYI for anyone wondering - Another option for the wiring is the Westfalia wiring kit with control module, you can order from pfjones.co.uk
Downside is shipping from the UK, and it assumes you have a 7-pin plug (so you need a 7-pin to 4-pin adapter for most US trailers). It does connect to existing wiring in a fairly non-destructive way with push-through clips that are removable.

Plus side is it integrates with other car systems, eg the parking system to disable reverse sensors while hitch is connected, and I believe some adjustments are made to the ABS, transmission program and drive select.
Also if you use an actual 7-pin connection to your trailer it will do bulb-out warnings on the dash.

It does require some re-coding with VCDS unlike the passive method, and if you have ACC the coding for that module is not well known in the USA.

[jerhofer]

Awesome write-up!!

Where did you get the carpeted mat for the trunk? I believe they have been discontinued since 2012 or 2013 :(

The carpeted mat came from a 2007 Passat wagon that we owned a few years ago. This is the third car I have used the mat in. I really like the little Velcro bottomed blocks that hold items in place.

[adt]

Jerhofer:

One more question: does the hitch stick out past the bumper? I can't tell on the photos.

Thanks again. Adam

[jerhofer]

Jerhofer:

One more question: does the hitch stick out past the bumper? I can't tell on the photos.

Thanks again. Adam

It does not stick out past the bumper.

[callaghan.]

Thanks for the write-up! I've had this hitch in my garage for over a month, dreading the install. How many hours did this take?

[jerhofer]

Thanks for the write-up! I've had this hitch in my garage for over a month, dreading the install. How many hours did this take?

Installing the hitch and the wiring took a day. It might go faster since you have this thread to follow. I had to look for certain items which slows you down. I could do another install in half the time.