efelker

George:

Got some more data off the VWVortex Forum for TRex. Here are two items that were posted.

1. I have the dealer installed hitch on a Touareg V8. It has a sticker limiting tongue weight to 616 pounds. Since tongue weight ought to be about 12% of the trailer weight, how can I safely haul 7700 pounds? The owners manual says the Treg is for Class I and II trailers only, Class II is 3500 pounds. The hitch ball is limited to 6 inches from the attachment pin...try finding an equalizer hitch with that short an arm. The Polack electric recepticle (7-way) has a wire to the pin usually used for an after-market electronic brake controller, but VW seems to have no idea where the other end of that wire is. Using the hitch recepticle, I have no brake lights. VW isn't sure why (maybe the installer missed this instruction? "Using 5051. Go to address 69 (trailer function). Go to 07 (control unit). Press 2 to reprogram modul for brake light function." VW customer service has been clueless on all of this, as have their dealers. I'd email 'em if their VW customer service site would recognize my VIN. Anyone know what to do about any of this?

2. QUOTE COPIED FROM INTERNAL MEMO sent to dealers on Sep 5, 2003:
All of the Touareg hitches that have been delivered to us have
> incorrect software loaded onto the control module/ "black box" (which is
> supplied with each hitch). This software causes warning lights to appear
> on the dashboard when the right turn signal is used, in conjunction with a
> 7 to 4 pole adapter. This problem has been diagnosed and a fix has been
> designed in the way of a software update. The incorrect module is part
> number 7L0 907 383 C. The incorrect modules can be easily "reflashed"
> using the VAG 5051 tool with the updated software CD. The correct
> software version is #8254. The update CD's and a Technical Bulletin will
> be sent to all dealers and QTM's as soon as we can get them duplicated and
> in the mail.
>
> Additionally, all hitches produced beginning week 36 (august 25) and
> later will have the correct control (7L0 907 383 E) modules packed in the
> hitch box. These hitches will not begin to arrive until late September.
> Until that time, all hitches installed MUST have the correct software
> flashed onto the control module. I will send another announcement as soon
> as the Technical Bulletin and CD's are on the way.

3. And finally, a copy of a VW TSB:


Extended Descriptions for Item V010307
Technical Bulletins
Group: 01
Number: 03-07
Date Published: 09/24/2003

Subject:
Volkswagen Technical Bulletin Update Programming (Flashing) Control Module for Towing Sensor (J345) to Accept 7-Pin to 4-Pin Adapter.

Model(s): Year(s):
Touareg with towing accessory package and control module Part number: 7L0907 383C. 2004

So it sounds like you need to be sure that your dealer has loaded the software patch or you'll get error messages.

Also, I'd agree with Ray about the WDH; but, I don't know if the T-Reg will even work with one. I don't think there is a ball mount that will fit the VW hitch that will allow attaching the arms. More importantly, I think the geometry & physics are all wrong for a WDH. The VW hitch is designed to basically REPLACE the existing stock bumper. It is mounted the same as the bumper (basically two plates on each side that have 4 bolts in each plate). The load from the hitch is applied in tension to the 8 bolts (that is, the force is applied as if you were pulling straight back on the heads of the bolt). You can see the plates in the image below. In most receiver installations, arms of the receiver run parallel to frame members and the force of the hitch would be applied at 90 degrees to the mount bolts. I just don't know how a WDH would transfer the load to the front axles of the T-Regg given the way the hitch is mounted. To my knowledge, the ball mount shown below is all that will work & you can see there is no way to hook up WDH arms. But I'm not an engineer, so I'll defer to those with far more technical knowledge.


But George, what does the owners manual say? Does it talk about WEIGHT CARRYING or WDH? There is a big diffderence.

This was the main reason I backed off the T-Regg. Could not find anyone at VW that could answer my towing hitch questions in a way that gave me confidence.


Ed