So,

The Octavia 3 only received the Blind Spot Assist with the facelift. That means it uses the 5Q generation control unit.

Of course, I'm not installing anything like that. Therefore, I'm using the OEM 5Q0 radar mounts with the 3D-printed adapters, just like @Lutz91 did in his Superb.

The OEM LED is integrated into the mirror glass, but I'm definitely not going back to that solution.

Through a bit of luck and some internet research, I discovered that another Volkswagen Group vehicle also uses the same Octavia 3 mirror caps.

This vehicle has the Blind Spot Assist from the factory with a version integrated into the mirror caps.

Thanks to @Lutz91 for finding the details.

So, I ordered a set of primed left and right mirror caps from the aftermarket, just to test them. VW charges €75 each, but I paid €35 for both aftermarket caps in Spain, plus a few euros for shipping home.

Thanks to @Lutz91 for the detailed research. The following parts are required:

Control units:

2Q0907686B

2Q0907685B

Sedan mounting bracket:

5E5907455A

5E5907456A

LED headlight washer mirror caps:

565949145

565949146

Exterior mirror caps

To be added if the correct parts are available

Wiring harness:

From my supplier in the Far East...

3D printer adapters for left and right

Die Steuergeräte sind komplett, der Kabelbaum auch. Der erste Außenspiegel komplett zerlegt

Die anderen Teile für OEM Retrofit in den Außenspiegel sind im Zulauf.

Gestern habe ich am Tisch die Steuergeräte aufgebaut. Firmware sauber neu geflasht auf beiden und einen für mich vermutlich passenden Datensatz aufgespielt.

Der Octavia 3 hatte nie die 2Q0 Steuergeräte verbaut, dadurch gibt es keinen originalen 2Q0 Datensatz dafür.

The control units are complete, as is the wiring harness. The first exterior mirror is completely disassembled.

The other parts for the OEM retrofit in the exterior mirrors are on their way.

Yesterday, I assembled the control units on the workbench. I cleanly reflashed the firmware on both and installed what I believe to be a suitable data set.

The Octavia 3 never had the 2Q0 control units installed, so there is no original 2Q0 data set for it.

Due to the change in the mirrors, the LED part number has also changed:

5E6949145

5E6949146

This should clarify which mirrors are being installed.

5 hours ago, Cairus said:

This should clarify which mirrors are being installed.

I didn't get what mirrors you had installed. Do you have reference number or what car they were from?

Octavia 4

But you need the Ground plade from Octavia 3

Edited 2 hours ago2 hr by Cairus

3 minutes ago, Cairus said:

Octavia 4

Thanks! Nice catch!

3 minutes ago, Cairus said:

But you need the Ground Blade from Octavia 3

Sorry, what is the Ground Blade?

The mounting base is screwed to the door. You have to detach the mirror from the base plate.

That's an excellent project and thanks for providing so much valuable info, I didn't know the mirrors from mk4 could be installed on the mounting bracket of the mk3! I also love that the LEDs will be integrated in the mirror casing instead of mirror elements since they are incredibly expensive and can easily be stolen I also heard that the 2Q0 radars are better than the 5Q0 ones because their range is bigger.

I have just finished installing BSD/RTA myself this week on my Skoda Octavia mk3 1.4 TSI 2017 using the 5Q0 radars and original mirror elements with BSD LEDs and dimming and I am happy how the system works:

I will follow your topic @Cairus to see how your work evolves! Good luck!

Just to mention that I bought the 5Q0 radars on ebay from Austria which were from a similar Skoda Octavia mk3 2017 and both units cost me 252€. The original used mirrors with dimming from ebay cost me 136€ (one was chipped), the cables I bought from aliexpress for around 50-60€, the radar mounting brackets I bought from skoda-parts.com for 24€/both, also needed to buy a couple of cables, pins and connectors from aliexpress for around 10-20€ max. So everything cost me around 500€

I'm from Austria... the parts were way too expensive. 5Q0 is rubbish, just upgrade to 2Q0. Much better.