As a content creator at keyfobprog.com and an automotive repair enthusiast, I recently delved into a puzzling issue for VW owners: the seemingly missing compass feature in some newer models. Specifically, I investigated the 2018 VW Alltrack and its compass functionality, using official erWin documentation to get to the bottom of this. What I discovered sheds light on why your Volkswagen compass might not be displaying and what might be the underlying technical reasons.
Volkswagen Golf Mk7 models are equipped with several antennas for various functions. According to the official service manual, these antennas are positioned around the vehicle as shown in this diagram:
While the diagram doesn’t explicitly label a “compass antenna,” it’s reasonable to assume that the Roof Antenna (RX5), marked as item 3, likely serves this purpose. This aligns with previous insights into Volkswagen compass antenna placements.
Further examination of the service manual reveals that the RX5 antenna’s connection depends on the vehicle’s options. It connects to either the Front Information Display Control Head (J685) or the Information Electronics Control Module 1 (J794). The schematic illustrates this connection:
To understand these components better, the service manual clarifies that J685 and J794 are distinct modules in vehicles equipped with the Discover Media system, typically found in SE and SEL trim levels in North America. However, in the base S model, like my Alltrack, the standard Composition Color head unit appears to integrate both J685 and J794 into a single dashboard component:
Component location diagrams further detail that J794, the Information Electronics module, is actually the CD player unit located in the glove compartment (item 9 in the first antenna location diagram). Interestingly, my Alltrack S lacks this glove compartment unit, while SE and SEL models I inspected at dealerships do include it. Item 3 in the Composition Color head unit diagram represents the head unit display, which is J685.
While the exact internal configuration of my dashboard remains unknown, the service manual suggests that J794 might be integrated within J685 in Composition Color systems. Referencing a scan of a 2018 Alltrack SE reveals the part number for J794 as 3Q0 035 844. As depicted in images online (like from eBay), this part number corresponds to the CD player unit with coaxial jacks for antenna connections. The scan data also lists a subsystem with part number 5G6 919 605, which is the dashboard display unit.
Address 5F: Information Electr. (J794) Labels:| 5G0-035-MIB-STD2.clb Part No SW: <b><u><span>3Q0 035 844</span></u></b> 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: <b><u><span>5G6 919 605</span></u></b> C HW: 5G6 919 605 C Component: ABT_Std-2 H50 8130 Serial number: VWZ6ZJT3190241 No fault code found.In contrast, the scan from my Alltrack S model shows only a single part number for Information Electronics: 5G6 035 868. While images of this specific component are elusive, it’s likely the combined display and module unit integrated into the dashboard.
Address 5F: Information Electr. (J794) Labels:| 5G0-035-MIB-ENT2.clb Part No SW: <b><u><span>5G6 035 868</span></u></b> 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.The most revealing discovery came when I investigated the physical antenna connection. Knowing that compass functionality could be enabled in 2017 and earlier models via VCDS coding, I suspected the wiring might still be present in my 2018 model. However, upon removing the headliner in the rear of my Alltrack, I found a surprising situation:
The roof antenna was a dummy! It had no wiring connections whatsoever. This suggests a cost-saving measure implemented for the 2018 models, possibly linked to changes in the infotainment system. Notably, the full VW Car-Net suite is not included in the 2018 S trim, unlike all 2017 models. Perhaps the “media” features of Car-Net became redundant with the updated base infotainment system.
To illustrate this further, consider these images. A 2017 Golf Wolfsburg Edition (base model) and a 2018 Alltrack SE both feature Car-Net communication buttons in the overhead console. My 2018 Alltrack S, however, lacks these buttons.
Wiring diagrams also indicate that the RX5 roof antenna can connect to J949, the “Control Module for Emergency Call Module and Communication Unit,” which likely corresponds to Car-Net. The manual locates J949 behind the instrument cluster. This aligns with the [75-Telematics] module, which has been previously discussed in relation to GPS location data. Here’s an excerpt from a log of that vehicle:
<b><u><span>Address 75: Telematics (J949)</span></u></b> 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.In conclusion, it appears that enabling the compass display on my 2018 Composition Color head unit (J794/J685) via VCDS is unlikely. This is due to the probable absence of a compass antenna input in this integrated unit, compounded by the discovery of a dummy roof antenna without any wiring. The lack of a separate CD player module (J794) in the glove compartment further reinforces this limitation. Without a Car-Net module either, there’s no alternative pathway to obtain compass data on the CAN bus using the existing hardware. While the technical feasibility of installing the J949 module (5QE 035 285) solely for compass input remains a question, the physical antenna limitation seems to be a significant hurdle.
I welcome any insights or comments on these observations from the community. What are your thoughts on this VW compass conundrum?
