DIY: Enable Rear Fog lights (Free Mod) on E92 M3

I originally posted about this here but am officially putting my DIY here to share with M3Post members.

Unlike a Euro-spec E9x's, the US-Spec cars do not have the rear fog lights option. Enabling the rear fog lights is an easy and free way to aid others to see you during heavy fog. This DIY involves nothing more than removing the light control switch assembly and trimming off four small tabs front the lower right button. All the electronics are already there and even the light on the dash works!

IMPORTANT: Check your local laws concerning the use of the rear fog lights. Please use this feature responsibly. Do not abuse it or blind others with it!

Parts

• 2011+ E9x (and some 2010): Requires no additional parts unless you want the Euro switch that has the rear fog light icon printed on the button.
• 2008-2010 (for 2010 you need to check yours): If you have an older E9x, you can do a search on M3Post.com for other DIY's using the Lego piece method or swapping out the entire switch assembly with a Euro switch.

Tools Required

• Trim removal tools
• Utility Knife
• Flat head screw driver

Before you begin:
Make sure your car is completely off before disconnecting any wire harnesses from the car. To be safe, you should disconnect your battery.

Step 1. Remove upper trim / ventilation duct

Study the image below. The yellow circles indicate where the rear retaining pins are located. You need to basically wiggle the trim panel so that the pins from behind will work itself free.

I used my trim removal tool on the bottom and top of the trim panel to work the it free. Once there's a slight gap on either side, you can use your finger tips to grab the trim and rock it free.

IMPORTANT: Be careful not to damage the surrounding leather if you have the extended leather package.



Step 2. Remove light control switch assembly

Study the image below. The yellow circles indicate where the rear retaining pins are located.

With the upper trim removed you have access to rear inside and grab the entire assembly. Once you have a hold of the assembly, rotate your wrist to rock the assembly and the pins should release.



Step 3. Remove wire harness connector

Removing the connector requires a two step process. The gray latch is held in place with a black tab. Simply press down on that tab then switch the gray latch down. The connector should start sliding out as you switch the gray latch. Once the latch is at a 90 degree angle the connector should be completely disconnected.



Below is an image showing the connector disconnected.



Step 4. Remove trim from light assembly

Using the proper trim removal tool or a flat head screw driver, unlatch the four clips holding the light assembly to the trim plate.



Step 5. Remove rear cover from light assembly

There are 6 clips total that will need to be unlatched. Using the proper trim removal tool or flat head screw driver, unlatch the 6 clips holding the back cover in place.

NOTE: Image below only shows the two clips on top. You should be able to see the other clips as you rotate the assembly.



Step 6. Remove circuit board

The circuit board simply lifts out.



Step 7. Remove the white button extensions

These white button extensions simply lift out.



Step 8. Unlatch lower button

In order to unlatch the clip holding the lower button in place, you will need a small flat head screw driver. Carefully unlatch the two black clips holding the button in place. See yellow circles below showing the black clips holding the white button in place.



Step 9. Trim off tabs from button

Notice the four little tabs around the back of the button. Carefully trim these tabs off with a sharp utility knife. These are the tabs that holds the button in place and restricts it from being functional.



Below shows the result after trimming.



Step 10. Reinstall light control switch assembly

The rest should be fairly straightforward.

• Press rear fog light button back in place on light control switch.
• Drop the two white button extensions into the rear of the buttons.
• Line up the green circuit board drop it in place.
• Reinstall rear of light assembly. Inspect each of the 6 clips to insure they have snapped in place.
• Reinstall light assembly onto trim plate. Inspect each of the 4 clips to insure they have snapped in place.
• Reinstall connector on the back of the light assembly.
• **This would be a good time to test the switch.
• Press light assembly trim back in place on the dash.
• Press the upper trim/air duct back in place on the dash.

Step 11. Final inspection

To activate the rear fog, simply turn on your car and press the lower right button on the light control switch.

Working dash light - check!



Working rear fog lights - check!



Closer inspection - check!



Disclaimer: Use this DIY at your own risk, I'm not responsible for any damage to your car.

Thanks for the guide brother! Just used it to enable the rear foggies on mine! Interesting note - on E90s, the light source doesn't come from the same place. It actually comes from the area right below the reverse light area.

Thanks for the writeup! Was able to do this on my 2011 m3 sedan. Took only 15 minutes. Works perfectly

great DIY just did mine, fantastic write up!

I'm so not mechanically inclined but this write up gave me the confidence to try this mod. Thanks so much!



OFF:



ON:

and now only use the fog lights if the visibility is less than 50 meter due to fog!

I see too many idiots all over the world driving with the fog lights on at night when there is no fog at all. Heavy rain does not count!

first time posting. wanted to say great work and thanks for saving me $130

Very nice DIY.

you mean everything is wired up and the bulb is present yet BMW just disabled the push button in the cabin? WTF? How dumb is that. At least it's easy to enable. wow...

Where's the kudos button? Guess this will have to do:



Great success!

shay2nak wrote

you mean everything is wired up and the bulb is present yet BMW just disabled the push button in the cabin? WTF? How dumb is that. At least it's easy to enable. wow...

Cost of manufacturing (as few changes to as few parts as possible) as well as local country laws on optional equipment both contribute to the configuration we see in production. I bet rear fogs are illegal in many places in the US.

Really! You should see how bad it rains over here not even 50 meters of visibility. Lack of visibility is not limited to fog only...

NRing wrote

............... Heavy rain does not count!

Thanks for the writeup. Took less than 15 minutes and worked as advertised. Any idea what the top button is for? I'm guessing front fogs if the assembly is used throughout the entire 3 series lineup.

TOOK ME 10 MINUTES
THANX

AWE90M3 wrote

Thanks for the writeup. Took less than 15 minutes and worked as advertised. Any idea what the top button is for? I'm guessing front fogs if the assembly is used throughout the entire 3 series lineup.

Your welcome. Glad you found it useful.

To answer your question on the top button, yes, that would be for the front fogs on non-M3s.

Great writeup. Thanks for posting. Just did mine - everything works like a charm. Quick note: Step 4 isnt necessary, you can do everything without removing light switch from trim panel.

Awesome post. Removing the button was the hardest part for me. Thanks!!

wow, that was very detailed and easy to follow DIY guide. thanks for posting. i have a feeling, i'm gonna mess something up. anyone from NJ do this?

ok, screw it. i gotta scratch this itch.

went to a local Autozone for the trim remover. they didn't carry one nor did they care. so, i used old credit cards to remove the trim. took a little more than 10 mins just to take it apart. damn. everything else was smooth sailing using the good 'ol swiss army knife. thanks OP!

Thanks for posting... Alot easier then my old 2008 335. The 2011 M included the plastic piece. The 2008 was done with modified cork from a bottle of wine. On 2nd thought the 335 might have been a little more enjoyable .

Just did this, took a little extra effort since I have an 08 E92 (no plastic stalk/ lego piece). My method was three fold:

1) Pen cap (acts as a plastic stalk to push the custom flat surface)
2) Pen cap connects to a small cut out credit card square plate (use any old credit card) - cut two squares to fit into the space
3) Sandwich double tape between the two credit card squares, adjust thickness as needed (by adding more double tape. Trail and error until you feel the two rubber buttons are pushed by the switch.

DIYs where you got to think on your feet, get creative = mad FUN!

Thanks for the write up! Going to try this after work tomorrow