So, I finally had a chance to review the
erWin documentation for the 2018 Alltrack and investigate this issue further. This post is long, but I hope informative. I found some interesting things. According to the service manual, there are a number of antennas on the Golf Mk7. Here are their locations:
There isn't any one antenna called out for compass duty, but if I had to guess, I'd say that it's probably part of the Roof Antenna (RX5) as shown in item 3. This is also consistent with previous information I've read about where VW puts the compass antenna.
Going further, the RX5 antenna connects to EITHER the Front Information Display Control Head (J685) OR the Information Electronics Control Module 1 (J794) depending on how the car is optioned. Per the schematic:
So, what are these devices? According to the service manual, J685 and J794 are separate components with the Discover Media system (SE and SEL models in North America). For the base S model, which is what I have, the standard Composition Color head unit seems to have J685 and J794 combined into the same component in the dashboard:
Looking at the component location diagrams, J794, the Information Electronics module, is actually the CD player unit in the glove compartment (item 9 in the first diagram). Note that my Alltrack S does NOT have this unit in the glove compartment. The SE and SEL models that I checked out at the dealership when I bought my car do have it. Item 3 in the second diagram is the head unit display, J685.
I don't actually know what's behind the dashboard on my car; it might just be an empty space, since the manual seems to imply that J794 is part of J685 with the Composition Color head units. For reference, I looked at a
scan of a 2018 Alltrack SE and found the part number for J794, which is 3Q0 035 844. As shown in the picture below (from
eBay), this is indeed the same component. You can also clearly see the coaxial jacks on the left side for the various antennas. In the code excerpt, note that a subsystem is listed with part number 5G6 919 605. This is the display inside the dashboard.
Code:
Address 5F: Information Electr. (J794) Labels:| 5G0-035-MIB-STD2.clb
Part No SW: 3Q0 035 844 B HW: 3Q0 035 844 B
Component: MU-S-S-US 722 0867
Serial number:
Coding: 02731200FF00000051220001001808009F0508D40120050002
Shop #: WSC 00066 790 07026
ASAM Dataset: EV_MUStd4CDELP 001001
ROD: EV_MUStd4CDELP_VW27.rod
VCID: 2E060434009226C7D04-807A
Operating And Display Unit 1:
Subsystem 1 - Part No SW: 5G6 919 605 C HW: 5G6 919 605 C
Component: ABT_Std-2 H50 8130
Serial number: VWZ6ZJT3190241
No fault code found.
For comparison, the scan from my vehicle only shows a single part number for Information Electronics, which is 5G6 035 868. I haven't been able to find any pictures of this component, but I assume it's the display and module combo in the dashboard.
Code:
Address 5F: Information Electr. (J794) Labels:| 5G0-035-MIB-ENT2.clb
Part No SW: 5G6 035 868 HW: 5G6 035 868
Component: MU-E--ER 671 8395
Serial number: 05061700021742
Coding: 02731200FF00000041220001001000009F0008D40000010000
Shop #: WSC 00066 790 00147
ASAM Dataset: EV_MUEnt4CGen2LGE 001041
ROD: EV_MUEnt4CGen2LGE_VW12.rod
VCID: 70B92CB0FA2058F7817-8025
No fault code found.
Now,
here's the real kicker: I wanted to see if the compass antenna wiring was even present in my vehicle, since it seems to be on the 2017 and earlier models. If you recall, those compasses can be enabled by simply turning on a few bits with . So, I pulled down the headliner in the back of my wagon and found this:
The roof antenna is a dummy! It doesn't have ANY wires going to it at all! I can't explain why this is, but I presume it's a cost-saving measure as a result of changing the infotainment systems for 2018. One thing that I noticed in particular is the full-blown VW Car-Net isn't included on the S-trim 2018s as it was with ALL of the 2017s. Perhaps the "media" features of Car-Net are unnecessary with with new base model infotainment system?
Here are some pictures to demonstrate. The first one is a 2017 Golf Wolfsburg Edition (essentially base model) that clearly shows the Car-Net communication buttons in the overhead console. Same for the 2018 Alltrack SE. My 2018 Alltrack S does NOT have these buttons.
The
wiring diagram also lists another schematic that shows the RX5 roof antenna connecting to J949, which is listed as "Control Module for Emergency Call Module and Communication Unit." If I had to take a guess, I'd say that was Car-Net. The manual also shows where it's located, which is behind the instrument cluster (item 3 below). This is the [75-Telematics] module that we were discussing earlier that had saved Dana's GPS locations. I've posted an excerpt of the
log from that vehicle below, too.
Code:
Address 75: Telematics (J949) Labels: 5QE-035-285.clb
Part No SW: 5QE 035 285 A HW: 5QE 035 285 A
Component: OCULowMQBUS 007 0568
Coding: 02730202C2823A017F1E06020000
Shop #: WSC 00066 790 07030
ASAM Dataset: EV_OCULowMQB 001006
ROD: EV_OCULowMQB.rod
VCID: C3C94CA94AB7B95908-8096
No fault code found.
So, to make a long story short, it seems that unless my 2018 Composition Color head unit (J794/J685) has an input for the compass antenna (unlikely), I am sorely out of luck in enabling the compass display with because I don't have the CD player module in the glove compartment that would normally accept this input. Seeing as how I have a faux antenna and the wiring isn't even there, I'm guessing that the 2018 radios don't have the proper input. Unfortunately, I also don't have a Car-Net module, so there's no alternative way to get this information on the CAN bus with my existing hardware. I'm wondering if it would be technically possible to install the J949 module (5QE 035 285) with only the compass input and see what it does. According to the manual, the only other connections are for emergency call and microphone input/output.
I'd be interested to hear any comments on my observations. What do you think?
