e36 LED Map Light Retrofit DIY - THE REAL DEAL

[Spyke]

Preface:

Okay, this has been tried before, but never properly executed. The halogens that BMW used have + running to the sides of the bulbs, and - to the tip. Since this is reversed polarity for LEDs, plugging them in results in no light of course. Simply swapping the wires, whether to the board or on the harness, does NOT work. This is because the wires are soldered to the board, then the current is run 2 or 3 different places within the circuit board utilizing a single wire for each function. Swapping wires may work for the map lights, but then your currents are crossed for the dome light, and it won't illuminate either. The only way around this previously was retrofitting an e46 or e39 light. So I took some time to work out the bugs and here's my contribution for you guys. You get to keep your e36 light where it belongs, and have LED goodness!

PS, for the DOME LIGHT make sure you get good LED bulbs, you want ones that correct the voltage. Otherwise solder in a small resistor to make up the difference between the Halogen vs LED bulbs. Typically a 1/2 or 1 watt resistor is all that's needed.

(You do NOT have to do this for the map lights.)

Tools Needed:

-Dremel/Drill with a rotary cutting blade
-Soldering gun
-Rosin core solder
-Wire
-Wire strippers/cutters
-Tape
-(x2) BA9s LED bulbs (I recommend the highest powered ones you can find)

DIY:

Basically, what we will be doing is cutting the paths of the + and - currents on the circuit board, and redirecting them to where they need to go to power the LEDs.

-Remove your dome light fixture: The cover snaps off easily. Then gently pry under the lip facing the rear of the car. The light fixture will pivot out towards the front of the car. Unplug the harness, and remove the circuit board from the housing. It is simply pressed in, and two grey tabs retain it via slots cut in the board. Just press them aside, while pushing up on the circuit board. Here is the board removed; the Red lines show where we will be cutting, and the sloppy arrows show where the currents will be redirected to:


Cuts made, Arrows Drawn by greggdrake, on Flickr

-I keep a bag of OEM wiring to harvest for projects, so I had the correct colors to use.


IMG_20111207_192633 by greggdrake, on Flickr

-Make your cuts in the Silver/Copper paths on the circuit board, as the first photo shows. You do NOT have to go deep, just until you see the board, and the connection is cleanly severed. Using small pieces of tape, you can tape the little wires in place while you solder them. Remove the tape and solder the other halves of the wires. Finished product should look like this:


Cuts made, Wires Soldered by greggdrake, on Flickr

-Install the LEDs, reinstall the board to the housing with the switches, and head to the car to test it. If everything works, slap that cover on, button everything up and enjoy!


Done! by greggdrake, on Flickr



*** e36 LED Key Light Retrofit DIY HERE ***

[Joylove]

Tidy job. What is the purpose of cutting and rerouting? Is it to change the function or drop the voltage?

[Spyke]

The reason is explained, but here it is again;

The halogen bulb BMW uses in the map light has ground current running to the tip of the bulb, and positive to the body of the bulb. This is "Reverse Polarity". LEDs run positive to the tip and ground to the body.

If you plug an LED in there without doing this work, it is receiving the positive & ground signals backwards, and therefore will not work. This is why we must sever the OEM connections and re-route the currents to power the bulb properly.

[Joylove]

Sorry I skimmed over that it seems. Thanks.

[Spyke]

No problem. At least it's clear if it comes up.

[wbarfels]

Nice. Now you just have to figure out how to do this for the cars that have dual rear bulbs! On mine I just swapped them out for the single led version, then butchered it to take a big 24 full size led board

Sure the the back passengers dont have a reading light, but 1. I dont ride back there, 2. books are now mostly on tablets (at least for me) and they have there own backlights, and of course 3. Which is that hell will freeze over before I ride in the back of my own car! (Unless there is a naked girl in the back anyways!)

[Spyke]

It would be the same process, just re-route the currents. If someone wants to drop off theirs or ship them to me, I can do a DIY for those as well.

Note: *I highly recommend everyone carry a hot naked girl in the car at all times anyways.

[3MPowered]

Subscribed so I can come back to it later, cheers! You're able to do this with coloured LEDs too right?

[Spyke]

Subscribed so I can come back to it later, cheers! You're able to do this with coloured LEDs too right?

Of course, the LED bulbs themselves will dictate color, so that's completely up to your personal preference.

[wbarfels]

I just used a Box knife and cut several times down the same line, and then used a small standard screwdriver to "scrape" the lines. Worked great (I cant find my dremel soooo),

[jmo69]

Note: *I highly recommend everyone carry a hot naked girl in the car at all times anyways.

Better than the 'dead trunk hooker'

[wbarfels]

Better than the 'dead trunk hooker'

It's too bad really, our trunks hold 2 small hookers max.....and with my sub box id probably have to cut them up and put them in a few bags to fit even one!

[e36fiend]

What kind of LEDs did you get?

[shatooi]

Of course, the LED bulbs themselves will dictate color, so that's completely up to your personal preference.

Do you know if this issue applies to all LED kits? I spoke w/a rep from ECS Tuning and they are claiming that this is not required, that the bulbs will work w/no modification.

[Spyke]

What kind of LEDs did you get?

I used SMD Ba9s LED bulbs

Do you know if this issue applies to all LED kits? I spoke w/a rep from ECS Tuning and they are claiming that this is not required, that the bulbs will work w/no modification.

I don't know about their specific bulb kit. If they don't work, let them know, then do this simple modification.

[hc1001]

It would be the same process, just re-route the currents. If someone wants to drop off theirs or ship them to me, I can do a DIY for those as well.

Note: *I highly recommend everyone carry a hot naked girl in the car at all times anyways.

The main rear lights that turn on when the doors open work without modification but the rear reading lights that you turn on with the button need the polarity changed. all you have to do is de-pin the purple/white wire and the brown wire next to it and swap the positions. For the LED bulb to work, the brown wire needs to be on the outside(pin 1) and the purple/white needs to be on the inside(pin 2).

Thanks for the DIY spyke. i just finished everything today except one of the bulbs in the kit is a blue led. gotta ask the seller for a exchange.

[Spyke]

The main rear lights that turn on when the doors open work without modification but the rear reading lights that you turn on with the button need the polarity changed. all you have to do is de-pin the purple/white wire and the brown wire next to it and swap the positions. For the LED bulb to work, the brown wire needs to be on the outside(pin 1) and the purple/white needs to be on the inside(pin 2).

Thanks for the DIY spyke. i just finished everything today except one of the bulbs in the kit is a blue led. gotta ask the seller for a exchange.

Awesome, thanks for confirming the rear c-pillars!

[wbarfels]

The main rear lights that turn on when the doors open work without modification but the rear reading lights that you turn on with the button need the polarity changed. all you have to do is de-pin the purple/white wire and the brown wire next to it and swap the positions. For the LED bulb to work, the brown wire needs to be on the outside(pin 1) and the purple/white needs to be on the inside(pin 2).

Thanks for the DIY spyke. i just finished everything today except one of the bulbs in the kit is a blue led. gotta ask the seller for a exchange.

OF course not everyone has those, and coming from my 94 325i that could easily fit a 24 LED plate down to the 2 small reading lamp size bulbs that my 99 uses was lame. The hole size is the same so I just used the single bulb light fixtures from my 94 and butchered the harness so they would turn on with the dome light.

I mean it's rare that Id have more then 2 people in my car, and even rarer that the person sitting in back would even need their own dedicated reading lamp. These days all of our devices have their own screen lighting anyways......SO for me it was a no brainer to ditch the the 2 small dual bulb unit in favor of a much larger single bulb that actually provides enough light to see when I need it.

[Spyke]

I have the single bulb version as well, which just uses a festoon style bulb. Replaced it with an SMD LED festoon bulb.

[wbarfels]

EDIT:

This really should be added to the DIY section. IT is fairly simple and solves a problem that is a real pita to get around with minimal modification.

[Spyke]

I can't get anything into the DIY section for some reason. It always says "Access Restricted"

[jamest007]

thanks for the ez fix i had the same problem with my leds

[mhayden]

just followed your DIY and it worked! thank you

[Spyke]

No problem guys!

PS, for the DOME LIGHT make sure you get good LED bulbs, you want ones that correct the voltage. Otherwise solder in a small resistor to make up the difference between the Halogen vs LED bulbs.

(You do NOT have to do this for the map lights.)

[ajsearle]

I am in the process of changing out my lights to LED. I sloppily tried to follow the instructions off memory and no computer for a day. Needless to say, I only soldered in the blue/white wires in the picture and tried to turn the individual side map lights and this was no success obviously. Then realized that my visor vanity lights stopped working, and also all the switches to my windows and sunroof stopped working. I am not sure what I fried or how to fix this or what to look for. I checked the fuses on the driver's side engine compartment and only one fuse designated as passenger airbag was fried. Not sure if that is related. I am stumped and not happy with myself. Anyone have any ideas? Everything literally worked perfect before putting these led's all over the interior and the license plate, and won't work now even after normal bulbs were put back in.