TLDR: Your A4 probably has the hardware fitted for the multi-colour ambient lighting, but it's not possible to illuminate the LEDs without serious work... It is however very easy to install your own LEDs! Here's some photos of my final result: https://www.dropbox.com/sh/hel6ny57u...upsDGN8Oa?dl=0

Hey everyone!

I love the interior ambient lighting in the A4, my car wasn't factory fitted with the Extended LED Interior Lighting Pack, it only has the LED Interior Lighting Pack with the white LEDs in the doors and centre console etc.

Here's a photo of my factory fitted LED Interior Lighting Pack (just passenger door as example): https://www.dropbox.com/s/kb66g22sx1...ting.jpeg?dl=0

Firstly, I wondered if it was possible that Audi simply fitted all A4 with the same hardware for the LEDs and simply limiting those of us who didn't upgrade to having just white lighting. This would make sense from a manufacturing perspective as there's less variations, less hardware and fewer parts, maybe even the option to up-sell the feature after it's been factory delivered.

I was optimistic about this, since my car is fitted with Side Assist and the Exit Warning system, which illuminates the door trims in bright red if you open the door when a vehicle (or even a person running as I tested) is approaching in your blind spot. If you have this installed, you can see the bright red illumination by going to "Car" in your MMI, then navigating to "Driving assistance" and then adjusting the brightness setting under "Side Assist".

This meant that there certainly are LEDs installed in the door trims that just don't illuminate while driving, even if they're just red LEDs.

Here's a photo of the Exit Warning system illuminating the door trims with the red LEDs: https://www.dropbox.com/s/axws7oxyvs...rning.jpg?dl=0

Speaking on the forums here and looking up the part numbers for the interior lighting, it quickly became apparent that the LED Interior Lighting Pack and Extended LED Interior Lighting Pack do in fact use different hardware with different part numbers.

Next, I decided to look more closely at those red LEDs for the Exit Warning system, since they produce the effect that I want. This meant removing the entire interior door trim panel.

What I discovered next was truly amusing...

It seems as though Audi fit every A4 with the RGB LEDs required for the Extended LED Interior Lighting Pack (at least, they did in my vehicle – Maybe they only do this when the LED Interior Lighting Pack or Exit warning system are fitted.).

But... they simply cut the wiring from the LED units, rendering them useless. Amazing! They spend the money installing the parts, but simply snip the wires if you didn't specify that option.

Here's a photo of the inside of the interior door trim panel: https://www.dropbox.com/s/qqu9qistof...-leds.jpg?dl=0
Red module: Exit Warning system LEDs
White module: Standard LED ambient lighting (not RGB)
Black module: RGB LED module installed, but with the wiring cut

Here's the RGB LED unit that was fitted with the wires cut: https://www.dropbox.com/s/olumk247mf...s-cut.jpg?dl=0

Here's the circuit inside of the module: https://www.dropbox.com/s/1nwxeq6mww...rcuit.jpg?dl=0

I initially thought that illuminating these LEDs would simply be a matter or re-attaching some wiring and providing power to the module. It turns out however that the module also required a data signal from the car with information such as the light colour and brightness etc. These LEDs are not set up in the same way as regular SMD 5050 RGB LEDs.

Even though they were installed, there was no simple way to illuminate the factory 'fitted' RGB LEDs.

My next idea was to simply provide 12v power to the red LEDs that illuminate the door trims for the Exit Warning system. This worked immediately, but there were some issues.

• Issue 1: Since the car was detecting the red LEDs being illuminated when they shouldn't be, the car treated this as a fault and disabled the Side Assist and Exit Warning systems, and showed a fault in the Virtual Cockpit.
• Issue 2: These are very bright red LEDs designed to flash for no more than a few seconds. Constantly illuminating them was causing them to give off more heat that I was confortable with. I'm confident this probably would have been okay, but I didn't want to cause any damage.

Finally, I settled on an easy solution with no issues! Here's what I did...

I purchased 4x 12v G4 LED units in red. These are very easy to find online, but I took my time to find one that only had LEDs on one side, and looked like they had an LED in a similar position to the circuit inside of the RGB module from the door (picture linked above).

These are the units I chose to use: G4 3 SMD LED 12V AC/DC WHITE / WARM WHITE / RED / BLUE BULB ~5W | eBay

Don't want red lighting? Chose any colour you like! When I tested some LEDs at home, the white looked great along side the white lighting of the rest of the interior!

These units were luckily VERY similar to the circuit inside of the RGB module from the door, here's a photo of them side-by-side: https://www.dropbox.com/s/orhmni28aw...-leds.jpg?dl=0

I then simply fit these units into the housing for the RGB modules. This required a little filing of the edges, but it was an easy 10 minute job.

Here's a photo of my new LED units fit inside the housing for the RGB modules: https://www.dropbox.com/s/42wogpa1mn...using.jpg?dl=0

It was then simply a matter of attaching some wiring to the pins, and then wiring this into the same circuit powering the white LEDs inside the door trim panels.

Done!

Here's some photos of my final result: https://www.dropbox.com/sh/hel6ny57u...upsDGN8Oa?dl=0

 

This is one of the best mod that I have seen, you obviously have played with wires before. Great DIY instructions.

 

I have the extended light package, but not the ambient lighting.

Does that mean all the wiring is intact and all i need is the data module? What is the data module?

What would be involved if i wanted to get the ambient light retrofitted when i already have the light package plus?

 

I didn't mention any data module, I'm not sure if that's a real thing...

If you have the white lighting 'strips' shining down in your door panels, or the white 'rings' in your cup holders, then you have the same as me. The above solution will work for you if you're willing to dismantle your door interior panels.

 

When I first start the car the lights along the door panels shine red but they quickly turn to white. If I could just get them to stay red to break up the monotony I would be a happy camper. I wonder if this is just a coding fix?

 

Sounds like you do have the full multi-colour ambient lighting. Are you 100% sure you can't change the colour settings in the MMI?

I remember reading that the Q7 did this, but you're in an A4 right?

 

Hey Joe have you played around with coding via OBDEleven or anything by chance?

I'm wondering if I can reattach the wiring to the pre-installed unit and then see if there's any coding that can enable it to work.

 

I don't think the wiring is present in the doors or body to do this, if that's the case then it would be an enormous job!

If you're in the same situation as me, you will only have the RGB LEDs in the smaller panels above the door pulls (the ones I illuminated red myself), the rest of the white lighting has white LEDs installed.

 

Yes, I'm in an A4 Premium Plus. I think only the Prestige model offers the flexibility to change lighting colors.

 

Are you in the US? When was your model produced?

Premium Plus models usually have the wires clipped for the RGB modules that can make it white. My Premium Plus A4 w/ Technology only has the recessed white lighting but the strip turns off right after it flashes red.

Maybe they made a mistake on your model? In that case sounds like you can probably program in different colors using OBDEleven or something.